Polyethylene Glycol (DB09287): A Comprehensive Monograph on its Pharmacological, Clinical, and Industrial Profile

Section 1: Introduction and Chemical Profile

1.1. Overview

Polyethylene glycol (PEG) is a synthetic, hydrophilic polyether compound derived from petroleum, recognized for its remarkable versatility and widespread use across numerous sectors.[1] It holds a unique dual identity, functioning both as a ubiquitous industrial polymer and as a crucial small molecule medication in clinical practice.[1] In the medical domain, PEG is most prominently known for its application as an osmotic laxative for the management of constipation and as a high-volume bowel cleansing agent essential for preparing the gastrointestinal tract for endoscopic and radiological procedures.[2] Beyond these primary uses, the inherent properties of the PEG polymer have led to its integration into a vast array of products and technologies, including cosmetics, food manufacturing, and advanced pharmaceutical drug delivery systems, most notably through the process of PEGylation.[1] This report provides a comprehensive monograph on polyethylene glycol, synthesizing information on its chemical nature, pharmacology, clinical applications, safety profile, and broader industrial uses.

1.2. Chemical Identity and Nomenclature

The fundamental structure of polyethylene glycol is that of a polymer composed of repeating ethylene glycol monomer units linked by ether bonds.[2] This structure is generally represented by the chemical formula

H−(O−CH2​−CH2​)n​−OH, with a corresponding generalized molecular formula of C2n​H4n+2​On+1​.[1] The classification of PEG as a "Small Molecule" by pharmacological databases like DrugBank (DB09287) is a functional categorization based on its use as a drug, contrasting it with large, complex biologics like monoclonal antibodies.[7] While chemically a polymer, its relatively simple repeating structure and physical mechanism of action align it with the functional class of small molecule drugs. This distinction is important, as its polymeric nature is fundamental to understanding its physical properties, minimal absorption, and diverse industrial applications.

The nomenclature for this compound varies depending on its molecular weight (MW) and the context of its use [1]:

• Polyethylene Glycol (PEG): This is the most common name, particularly within the biomedical and pharmaceutical fields. It typically refers to oligomers and polymers with a molecular mass below 20,000 g/mol.[1]
• Polyethylene Oxide (PEO): This term is more prevalent in the field of polymer chemistry and is generally used for polymers with a molecular mass exceeding 20,000 g/mol.[1]
• Polyoxyethylene (POE): This is a broader chemical name that can refer to a polymer of any molecular mass.[1]
• Macrogol: This is the international nonproprietary name (INN) or generic name for polyethylene glycol when used as a laxative. The name is often appended with a number that represents the average molecular weight of the polymer, such as macrogol 3350 or macrogol 4000.[1]

Key chemical and regulatory identifiers for polyethylene glycol include CAS Number 25322-68-3, DrugBank ID DB09287, UNII (Unique Ingredient Identifier) 3WJQ0SDW1A, and the E number E1521 for its use as a food additive.[1]

1.3. Physicochemical Properties

The physicochemical properties of polyethylene glycol are intrinsically linked to its molecular weight, which dictates its physical state, solubility, and ultimately, its function in various applications.[1]

• Molecular Weight (MW): PEG is a polydisperse polymer, meaning a given sample contains a distribution of molecules with varying chain lengths and thus, varying molecular weights. It is commercially available across a vast spectrum of average molecular weights, from low hundreds to several million g/mol.[1] The number included in the name of a specific PEG product, such as PEG 3350, denotes its average molecular weight in g/mol.[1] The molar mass of a specific PEG molecule can be calculated using the formula 44.05n+18.02 g/mol, where 'n' is the number of repeating ethylene glycol units.[1]
• Physical State and Appearance: The physical state of PEG is directly dependent on its molecular weight. Low-MW PEGs (e.g., PEG 200, PEG 400) exist as clear, colorless, viscous liquids at room temperature.[6] As the molecular weight increases, the polymer transitions into a soft, waxy solid, and high-MW PEGs (e.g., PEG 3350, PEG 4000) are typically supplied as white or off-white flakes or powders.[7]
• Solubility: A defining characteristic of PEG is its high solubility in water, which is essential for its osmotic activity in the gastrointestinal tract.[1] This hydrophilicity arises from the ether oxygen atoms in its backbone, which can form hydrogen bonds with water molecules.[2] It is also soluble in a range of organic solvents, including methanol, ethanol, and benzene, but is insoluble in others like diethyl ether and hexane.[1]
• Stability and Storage: PEG is a stable compound under typical storage conditions, though it is incompatible with strong oxidizing agents.[6] It has a high boiling point of over 250 °C.[6] For pharmaceutical use, it should be stored in a closed container at room temperature, away from heat, moisture, and direct light.[9]

Section 2: Core Pharmacology

2.1. Mechanism of Action: An Osmotic Effect

The primary pharmacological effect of polyethylene glycol as a laxative is mediated through a purely physical, osmotic mechanism.[10] When administered orally, the large, hydrophilic PEG polymers are not significantly absorbed from the gastrointestinal tract.[2] Within the colonic lumen, the polymer chains, with their numerous ether oxygen atoms, act as a scaffold for hydrogen bonding with water molecules.[2] This potent water-binding capacity effectively sequesters a large volume of water within the gut, preventing its reabsorption into the bloodstream.[2]

The retention of this excess water leads to two key physiological consequences. First, it significantly increases the water content of the stool, resulting in a softer, more pliable stool consistency. Second, the increased volume of the luminal contents exerts an osmotic pressure that expands the colon.[2] This distension stimulates stretch receptors in the colonic wall, which in turn triggers propulsive muscle contractions (peristalsis), accelerating the transit of fecal matter through the colon and facilitating more frequent and less strained bowel movements.[12]

A crucial aspect of PEG's pharmacological profile is its biological inertness within the colon. Unlike other osmotic laxatives such as lactulose or sorbitol, PEG is not metabolized or fermented by the resident colonic bacteria.[14] This lack of fermentation means that there is no significant production of intestinal gas (e.g., hydrogen, methane) or short-chain fatty acids. This "clean" osmotic profile is directly responsible for PEG's superior tolerability, as it avoids the common side effects of bloating, flatulence, and cramping that are characteristic of fermentable laxatives.[14]

2.2. Pharmacokinetics: A Profile of Minimal Systemic Exposure

The pharmacokinetic profile of orally administered polyethylene glycol, particularly high-MW variants like PEG 3350, is characterized by extremely limited systemic absorption and exposure. The majority of the drug exerts its effect locally within the gastrointestinal lumen and is eliminated unchanged in the feces.

2.2.1. Absorption

High molecular weight PEGs are poorly absorbed from the gastrointestinal tract following oral ingestion, a property that is central to their safety and mechanism of action.[2] Multiple studies have quantified this minimal absorption, consistently showing that less than 1% of an administered dose is absorbed systemically.[15] One clinical study reported that the fraction of a PEG 3350 dose excreted in the urine, an indicator of systemic absorption, ranged from just 0.15% to 0.58%.[15] This poor permeability is directly related to the large size of the polymer molecule. Absorption is inversely dependent on molecular weight; lower-MW PEGs are more readily absorbed across the intestinal epithelium compared to their high-MW counterparts.[18]

2.2.2. Distribution

Due to the negligible systemic absorption of high-MW PEG, data on its distribution throughout the body following oral administration are limited. For the very small fraction that does enter circulation, one study involving a large 140-gram dose for bowel preparation reported a mean volume of distribution of 48,481 L, though the clinical significance of this for standard laxative doses is unclear.[7] In contrast, the distribution of other drugs can be dramatically altered through the process of PEGylation—the covalent attachment of PEG chains. This pharmaceutical strategy leverages the physicochemical properties of PEG to modify the distribution and retention of therapeutic proteins and nanoparticles, often enhancing their accumulation in specific tissues like tumors.[19]

2.2.3. Metabolism

Polyethylene glycol 3350 is considered metabolically inert within the gastrointestinal tract, where it is not subject to enzymatic degradation by human enzymes or fermentation by gut bacteria.[7] For the small fraction of PEG that is absorbed systemically, metabolism is again dependent on molecular weight. Lower-MW PEGs (e.g., PEG 400) can undergo some metabolism, with studies suggesting up to 25% of an absorbed dose may be oxidized by alcohol dehydrogenase and potentially cytochrome P450 enzymes to form corresponding carboxylic acids.[17] However, higher-MW PEGs (typically >5,000 Da), such as those used for laxative purposes and in PEGylation, show little to no metabolism.[18] Ethylene glycol, a toxic precursor, is not considered a metabolite of PEG 3350 in humans.[17]

2.2.4. Excretion

The primary route of elimination for an oral dose of PEG 3350 is fecal. The vast majority of the ingested, unabsorbed polymer passes through the gastrointestinal tract and is excreted unchanged in the stool. Studies have demonstrated that approximately 93% of an administered dose can be recovered in the feces over a period of 240 hours.[7] The small fraction that is absorbed into the systemic circulation is cleared from the body by the kidneys via passive glomerular filtration and excreted in the urine.[15]

Pharmacokinetic studies have defined the time course of this minimal systemic exposure. Following oral administration, peak plasma concentrations of PEG 3350, though very low, typically occur between 2 to 4 hours.[15] The plasma half-life is estimated to be approximately 4 to 6 hours, and plasma levels generally decline to unquantifiable or near-zero levels within 18 to 24 hours of dosing.[15]

2.3. Pharmacodynamics

The pharmacodynamic effects of polyethylene glycol relate to the timing and nature of its impact on gastrointestinal function.

• Onset of Action: For the treatment of occasional or chronic constipation, the onset of a therapeutic response (i.e., a bowel movement) is gradual, typically occurring within 1 to 4 days of initiating therapy.[2] This contrasts with its use for bowel preparation, where the high doses induce a much more rapid onset of copious diarrhea, usually within 1 to 2 hours of ingestion.[7]
• Effect on Gastrointestinal Transit: Clinical studies have demonstrated that PEG 3350 effectively accelerates overall gut transit, as measured by a decrease in oro-cecal transit time.[26] However, these studies have also revealed a seemingly paradoxical effect on the upper gastrointestinal tract: PEG causes a significant delay in gastric emptying.[26] This phenomenon is likely a physiological response to the osmotic load presented to the duodenum, which triggers neurohormonal feedback mechanisms to slow the rate at which the stomach releases its contents. This delayed gastric emptying provides a mechanistic explanation for the upper gastrointestinal side effects, such as nausea and bloating, that some patients experience before the laxative effect begins.[10] This is a clinically important consideration, as PEG could potentially exacerbate symptoms in patients with pre-existing gastroparesis or other gastric motility disorders.

Section 3: Clinical Applications in Gastroenterology

3.1. Management of Constipation

Polyethylene glycol 3350 is a cornerstone in the management of constipation. Its primary FDA-approved indication is for the treatment of occasional constipation in adults and adolescents aged 17 years and older.[2] Beyond this, its efficacy and safety have established it as a first-line agent for the management of chronic idiopathic constipation.[2]

Numerous randomized controlled trials (RCTs) have consistently demonstrated the superiority of PEG 3350 over placebo. These studies show statistically significant improvements in key clinical endpoints, including an increased frequency of bowel movements, improved stool consistency (i.e., softer stools), and a reduction in straining during defecation.[2] Reflecting this robust body of evidence, a comprehensive systematic review published in 2020 assigned polyethylene glycol a Level I Evidence, Grade A Recommendation for the treatment of chronic constipation, the highest level of endorsement.[29] Its favorable tolerability profile, particularly the lower incidence of cramping and gas compared to other osmotic laxatives like lactulose, makes it a preferred agent for both patients and clinicians.[2]

3.2. Bowel Preparation for Endoscopic and Radiological Procedures

Polyethylene glycol is indispensable for achieving adequate colonic cleansing prior to diagnostic and surgical procedures, most notably colonoscopy and barium enema X-ray examinations.[2] For this indication, high-volume solutions of PEG 3350 are used to induce a profuse, watery diarrhea that effectively purges the colon of all fecal matter.

These bowel preparation formulations are distinct from the single-ingredient laxative powders. They are typically multi-component kits that combine PEG 3350 with a balanced mixture of electrolytes, such as sodium sulfate, sodium bicarbonate, sodium chloride, and potassium chloride.[3] The inclusion of these electrolytes is critical to prevent clinically significant fluid and electrolyte shifts in the body, which would otherwise occur due to the large volume of fluid being passed.[3] Some modern formulations also incorporate ascorbic acid, which contributes to the osmotic effect and may allow for a lower total volume of solution to be consumed.[32]

Dosing regimens for bowel preparation have evolved to improve both efficacy and patient tolerance. While a single-dose regimen, in which the entire 4-liter volume is consumed the evening before the procedure, was historically common, the split-dose regimen is now the preferred method.[32] In a split-dose regimen, the patient consumes a portion of the solution (e.g., 2 liters) the evening before the colonoscopy and the remaining portion on the morning of the procedure. Clinical studies have shown that this approach provides superior bowel cleansing, particularly in the right side of the colon, compared to the single-dose evening-only regimen.[34] Ongoing Phase 4 clinical trials continue to investigate and optimize bowel preparation protocols, including comparisons of PEG with other agents like sodium picosulfate and its use in pre-operative bowel cleansing for urologic and gynecologic surgeries.[35]

3.3. Dosage, Administration, and Formulations

The dosage and administration of polyethylene glycol vary significantly depending on the clinical indication and patient population.

• For Constipation in Adults: The standard over-the-counter (OTC) and prescription dose for adults is 17 grams of PEG 3350 powder. This is typically measured using the bottle cap or a single-dose packet and should be dissolved completely in 4 to 8 ounces (120 to 240 mL) of a beverage. Suitable liquids include water, juice, coffee, tea, or soda. The solution is then taken orally once daily as needed.[2]
• For Constipation in Pediatrics (Off-Label Use): Dosing in children is not standardized by the FDA and is typically based on body weight. For fecal impaction, guidelines recommend a dose of 1 to 1.5 g/kg/day for a short duration of 3 to 6 days. For the management of chronic constipation, an initial dose of 0.4 g/kg/day is often used, followed by a maintenance dose adjusted to effect, generally ranging from 0.2 to 0.8 g/kg/day.[2]
• For Bowel Preparation in Adults: This indication requires the consumption of a much larger volume. A typical regimen involves reconstituting the provided powder in 2 to 4 liters of water and drinking the solution in divided portions. A common instruction is to drink 240 mL (8 ounces) every 10 to 15 minutes until the entire volume is consumed or until the rectal effluent is clear and free of solid matter.[30] Chilling the solution prior to administration can improve its palatability.[3]

The following table provides a consolidated reference for standard dosing regimens.

Table 1: Standard Dosage and Administration of Polyethylene Glycol

Indication	Patient Population	Formulation	Dosage	Administration Instructions & Key Notes
Occasional/Chronic Constipation	Adults & Adolescents (≥17 years)	PEG 3350 Powder (e.g., MiraLax)	17 g once daily	Dissolve one capful or packet in 4-8 oz of liquid (water, juice, etc.) and drink. Onset of action is 1-4 days. OTC use should not exceed 7-14 days without physician consultation.2
Fecal Impaction	Pediatrics (>2 years)	PEG 3350 Powder	1 to 1.5 g/kg/day	Administer for 3 to 6 consecutive days. Use is off-label and requires physician supervision.2
Chronic Constipation	Pediatrics (>2 years)	PEG 3350 Powder	Initial: 0.4 g/kg/day; Maintenance: 0.2 to 0.8 g/kg/day	Dose should be titrated to achieve desired effect. Use is off-label and requires physician supervision.2
Bowel Preparation (Split-Dose)	Adults	PEG 3350 + Electrolytes Solution (e.g., GoLYTELY, MoviPrep)	Total volume of 2-4 L, split into two doses	Dose 1 is taken the evening before the procedure. Dose 2 is taken the morning of the procedure, ~12 hours after Dose 1 and completed at least 2-3.5 hours prior to colonoscopy. Considered superior for cleansing.32
Bowel Preparation (Evening-Only)	Adults	PEG 3350 + Electrolytes Solution (e.g., GoLYTELY, MoviPrep)	Total volume of 2-4 L, split into two doses on the same evening	Dose 1 is taken in the evening. Dose 2 is taken ~1.5 hours after starting Dose 1. An alternative regimen, may be less effective than split-dosing.32

Section 4: Comprehensive Safety and Risk Management Profile

4.1. Adverse Effects

The safety profile of polyethylene glycol is generally favorable, with most adverse effects being mild, transient, and directly related to its osmotic mechanism of action. However, rare but serious adverse events can occur, particularly with the high-volume formulations used for bowel preparation or in vulnerable patient populations.

• Common Adverse Effects: The most frequently reported side effects are gastrointestinal in nature. These include nausea, abdominal bloating, abdominal cramping, flatulence, and diarrhea.[9] In clinical trials for bowel preparation, these symptoms were reported by up to 50% of patients and are considered an expected consequence of the large osmotic load and fluid intake.[27] For standard-dose constipation treatment, these effects are typically much milder.
• Serious Adverse Effects: Although rare, several serious adverse events have been associated with PEG use:
• Fluid and Electrolyte Abnormalities: Significant dehydration and disturbances in serum electrolytes (e.g., hyponatremia, hypokalemia) are the most critical risks, primarily associated with large-volume bowel prep solutions. These imbalances can lead to severe secondary complications.[3]
• Cardiac Arrhythmias: There are rare postmarketing reports of serious cardiac arrhythmias, including atrial fibrillation and asystole, which are thought to be secondary to significant fluid and electrolyte shifts.[3]
• Seizures: Generalized tonic-clonic seizures have been reported, even in patients with no prior history of seizures. These events are often linked to severe electrolyte abnormalities, particularly hyponatremia, induced by the osmotic load.[3]
• Renal Injury and Metabolic Acidosis: While oral PEG 3350 is not directly nephrotoxic, dehydration can lead to acute kidney injury. Furthermore, case studies have documented severe metabolic acidosis and renal injury following massive oral ingestion, prolonged use of intravenous infusions containing PEG as a vehicle, or intra-peritoneal leakage of PEG solutions during surgery.[2]
• Hypersensitivity Reactions: Allergic reactions can occur, ranging from mild urticaria (hives) and rash to more severe angioedema and, in very rare instances, anaphylaxis.[27] The increasing ubiquity of PEG in consumer and medical products may be contributing to pre-sensitization in some individuals, potentially explaining these rare but severe reactions.
• Colonic Mucosal Ulcerations and Ischemic Colitis: The use of osmotic laxatives for bowel preparation can cause aphthous ulcerations of the colonic mucosa. More severe cases of ischemic colitis have also been reported.[3]

4.2. Contraindications, Warnings, and Precautions

The use of polyethylene glycol is contraindicated in certain clinical situations, and specific warnings and precautions must be observed to ensure patient safety.

• Absolute Contraindications: PEG should not be used in patients with known or suspected gastrointestinal obstruction, ileus (paralysis of the bowel), gastric retention, bowel perforation, or toxic colitis/toxic megacolon.[2] An assessment to rule out bowel obstruction should be performed before initiating treatment.[2]
• Warnings and Precautions:
• Renal Impairment: Patients with kidney disease are at higher risk for fluid and electrolyte abnormalities. PEG should be used with caution in this population. Adequate hydration must be ensured, and clinicians should consider monitoring baseline and post-procedure laboratory values (electrolytes, creatinine, BUN) when used for bowel preparation.[3]
• Cardiac Disease: Patients with a history of congestive heart failure, uncontrolled arrhythmias, or recent myocardial infarction are more susceptible to complications from fluid and electrolyte shifts. Pre- and post-procedure ECGs may be warranted in high-risk individuals undergoing bowel preparation.[3]
• Risk of Aspiration: Caution is advised when administering PEG to patients with an impaired gag reflex, semiconscious patients, or those prone to regurgitation. These patients should be observed closely during administration, especially if given via a nasogastric tube.[3]
• Interaction with Starch-Based Thickeners: A critical and specific precaution exists for patients with dysphagia who require thickened liquids. Polyethylene glycol can break down the structure of starch-based thickeners, leading to a loss of viscosity of the liquid. This can significantly increase the risk of choking and aspiration. For these patients, a xanthan gum-based thickener should be used instead, or an alternative laxative should be considered.[2]

4.3. Use in Special Populations

The risk-benefit profile of polyethylene glycol must be carefully considered in specific patient populations.

• Pediatric Patients: The FDA has not officially approved PEG for use in children under the age of 17; therefore, its use in this population is common but considered off-label.[2] While generally effective for childhood constipation and fecal impaction, its long-term safety profile is an area of concern. The FDA has received numerous postmarketing reports of neuropsychiatric adverse events in children on prolonged PEG therapy. These events include seizures, tremors, tics, obsessive-compulsive behaviors (e.g., repetitive chewing), paranoia, mood swings, anxiety, and aggression.[2] A causal link between PEG and these events has not been definitively established, and the underlying mechanism remains unknown. It is unclear if these events are a direct pharmacological effect, a consequence of subtle chronic electrolyte shifts, or a reporting artifact. Nevertheless, this safety signal necessitates careful monitoring of pediatric patients on long-term PEG for any new or worsening behavioral or neurological symptoms.
• Geriatric Patients: Elderly patients, particularly those in nursing homes, have shown a higher incidence of diarrhea when taking the standard 17-gram daily dose for constipation. If diarrhea occurs in this population, the dose should be reduced or the medication discontinued to prevent dehydration and related complications.[25]
• Pregnancy and Lactation:
• Pregnancy: PEG is designated as Pregnancy Category C. However, because systemic absorption is minimal, it is considered unlikely to cause harm to the developing fetus. Despite a lack of formal, large-scale research in pregnant women, the American Academy of Family Physicians (AAFP) considers polyethylene glycol a drug of choice for the treatment of chronic constipation during pregnancy due to its favorable safety profile.[2]
• Lactation: There are no specific recommendations on the manufacturer's label for use in breastfeeding women. As with pregnancy, the poor systemic absorption of PEG makes it highly unlikely that clinically significant amounts would be excreted into breast milk.[2]

4.4. Drug Interactions

Drug interactions with polyethylene glycol are primarily pharmacokinetic or pharmacodynamic in nature, rather than metabolic.

• Pharmacokinetic Interactions: The principal interaction mechanism is physical. By inducing diarrhea and accelerating gastrointestinal transit, especially during high-volume bowel preparation, PEG can decrease the contact time and thus the absorption of other concurrently administered oral medications. To mitigate this effect, it is recommended that no other oral medications be taken within one hour of starting a PEG bowel prep solution.[3]
• Pharmacodynamic Interactions:
• Diuretics: Co-administration with diuretics, particularly loop diuretics like furosemide, significantly increases the risk of dehydration and electrolyte disturbances (e.g., hypokalemia). This combination requires caution and may necessitate electrolyte monitoring.[40]
• Drugs that Lower Seizure Threshold: Caution is advised when using PEG in patients taking medications that can lower the seizure threshold, such as tricyclic antidepressants. The potential for PEG-induced electrolyte abnormalities can further increase the risk of seizures in these patients.[3]
• Other Laxatives: Combining PEG with other laxatives, such as stimulants (e.g., bisacodyl, senna) or other osmotics, increases the risk of additive gastrointestinal side effects, primarily diarrhea and dehydration. Concurrent use of stimulant laxatives during a PEG bowel prep may also increase the risk of colonic mucosal ulcerations.[3]
• Anticholinergic Agents: Drugs with anticholinergic properties (e.g., atropine, some antidepressants, some antihistamines) can decrease intestinal motility. This can counteract the therapeutic effect of PEG.[7]

The following table summarizes key drug interactions for clinical reference.

Table 2: Clinically Significant Drug Interactions with Polyethylene Glycol

Interacting Drug/Class	Potential Effect	Mechanism of Interaction	Clinical Management/Recommendation
All Oral Medications (during bowel prep)	Decreased absorption and efficacy of the co-administered drug.	Accelerated GI transit reduces time for drug absorption.	Administer other oral medications at least 1 hour before starting the PEG bowel prep solution.3
Loop Diuretics (e.g., furosemide, torsemide)	Increased risk of dehydration, electrolyte imbalance (especially hypokalemia), and subsequent kidney injury.	Additive fluid and electrolyte loss from both diuretic and osmotic laxative effects.	Use with caution. Ensure adequate hydration. Consider monitoring serum electrolytes, especially in at-risk patients.40
Stimulant Laxatives (e.g., bisacodyl, senna)	Increased risk of severe diarrhea, dehydration, and cramping. May increase risk of mucosal ulceration during bowel prep.	Additive laxative effects.	Avoid routine co-administration. If used together (e.g., in some bowel prep kits), follow instructions precisely and monitor for severe side effects.3
Drugs Lowering Seizure Threshold (e.g., tricyclic antidepressants, bupropion)	Increased risk of seizures.	PEG-induced electrolyte abnormalities (e.g., hyponatremia) can lower the seizure threshold further.	Use with caution, especially in patients with a history of seizures. Ensure adequate hydration and correct any pre-existing electrolyte imbalances.3
Anticholinergic Agents (e.g., atropine, diphenhydramine)	Decreased therapeutic efficacy of PEG.	Anticholinergic effect slows intestinal motility, opposing the pro-motility effect of PEG.	Monitor for reduced laxative effect. The combination may be less effective.7

Section 5: Comparative Analysis of Laxative Therapies

To fully appreciate the clinical role of polyethylene glycol, it is essential to compare it with other major classes of laxatives in terms of mechanism, efficacy, and safety.

5.1. An Overview of Laxative Classes

Laxatives are broadly categorized based on their primary mechanism of action [11]:

• Bulk-Forming Laxatives: These agents, such as psyllium (Metamucil) and methylcellulose (Citrucel), consist of soluble or insoluble fiber that absorbs water in the intestine. This increases the mass and water content of the stool, which stimulates peristalsis. They are generally considered the gentlest class and are often recommended as a first-line approach, but they can take 2-3 days to work and may cause bloating and gas.[11]
• Osmotic Laxatives: This class works by drawing water into the colonic lumen via osmosis, softening the stool and increasing intraluminal volume. Examples include polyethylene glycol, lactulose, sorbitol, and saline laxatives (e.g., magnesium hydroxide, magnesium citrate). Their onset for constipation is typically 2-3 days.[11]
• Stimulant Laxatives: These agents, including bisacodyl (Dulcolax) and senna (Senokot), directly stimulate the enteric nerves and smooth muscle of the colon, increasing intestinal motility and secretions. They are faster-acting (6-12 hours) but are associated with a higher incidence of abdominal cramping. Long-term, regular use is generally discouraged due to concerns about causing laxative dependency.[11]
• Emollient Laxatives (Stool Softeners): This class, primarily represented by docusate sodium (Colace), acts as a surfactant to lower the surface tension of the stool, allowing water and fats to penetrate and soften it. They are intended to prevent straining rather than actively induce a bowel movement.[42]

Table 3: Comparative Profile of Major Laxative Classes

Laxative Class	Examples	Mechanism of Action	Typical Onset of Action (for Constipation)	Common Side Effects	Clinical Niche/Role
Bulk-Forming	Psyllium, Methylcellulose, Polycarbophil	Increases fecal mass and water content, stimulating peristalsis.	2-3 days	Bloating, gas, cramping. Must be taken with sufficient water to avoid obstruction.	First-line for chronic constipation; mimics dietary fiber. Good for long-term maintenance.11
Osmotic (PEG)	Polyethylene Glycol 3350 (MiraLax)	Retains water in the colon via hydrogen bonding, softening stool and increasing volume. Non-fermentable.	1-4 days	Bloating, nausea, diarrhea. Less gas and cramping than other osmotics.	First-line for chronic constipation; highly effective and well-tolerated. Also used for bowel prep at high doses.2
Osmotic (Sugars/Salts)	Lactulose, Sorbitol, Magnesium Hydroxide	Poorly absorbed sugars/salts draw water into the colon via osmosis. Sugars are fermented by bacteria.	2-3 days	Bloating, flatulence, cramping (especially with sugars). Magnesium can cause electrolyte issues in renal impairment.	Effective for constipation, but often with more side effects than PEG. Magnesium salts are faster-acting.42
Stimulant	Bisacodyl, Senna	Directly stimulates enteric nerves and colonic muscle, increasing motility and secretion.	6-12 hours	Abdominal cramps, diarrhea, electrolyte imbalance. Risk of dependency with chronic use.	For intermittent or rescue use when faster relief is needed. Generally not for long-term daily use.11
Stool Softener (Emollient)	Docusate Sodium (Colace)	Surfactant action allows water and fats to mix into the stool, softening it.	1-3 days	Minimal side effects.	Primarily for preventing straining in post-operative patients or those with hemorrhoids/anal fissures. Efficacy for treating existing constipation is debated.42

5.2. Efficacy and Safety of PEG vs. Other Agents

Direct and indirect comparisons from clinical trials and systematic reviews have clarified PEG's standing relative to other laxatives.

• PEG vs. Lactulose: Multiple systematic reviews and meta-analyses have concluded that polyethylene glycol is superior in efficacy to lactulose for the treatment of chronic constipation in both adults and children. PEG leads to a higher frequency of bowel movements and better stool consistency. Furthermore, PEG is associated with better tolerability, causing significantly less nausea and flatulence, a difference attributed to its non-fermentable nature.[29]
• PEG vs. Docusate: The evidence strongly favors polyethylene glycol over docusate. PEG is a highly effective laxative for treating constipation, whereas the efficacy of docusate is questionable. Several systematic reviews have concluded that docusate is no more effective than a placebo for treating constipation.[29] Therefore, PEG is considered a much more reliable and effective option, particularly for conditions like medication-induced constipation where a stool softener alone is often insufficient.[47]
• PEG vs. Stimulant Laxatives: The choice between PEG and a stimulant laxative depends on the clinical context. Stimulants provide faster relief but at the cost of more significant side effects, notably abdominal cramping.[45] For the long-term management of chronic constipation, PEG is generally preferred due to its gentler mechanism and better safety profile for daily use.[28] The standard clinical approach is to initiate therapy with a bulk-forming or osmotic laxative like PEG, reserving stimulants for intermittent use or for patients who do not respond to first-line agents.[11]

5.3. Evidence-Based Clinical Standing

The clinical standing of polyethylene glycol for chronic constipation is exceptionally strong and supported by high-quality evidence. A 2020 systematic review of over-the-counter therapies for chronic constipation, which evaluated studies based on rigorous criteria, assigned polyethylene glycol a Grade A recommendation based on Level I (Good) evidence.[29] This represents the highest level of clinical endorsement and solidifies its position as a first-line therapeutic agent. While older reviews noted a general lack of large, head-to-head trials comparing different laxative classes [49], the body of evidence accumulated over the past two decades has consistently affirmed the superior or equivalent efficacy and favorable safety profile of PEG compared to other commonly used laxatives.

Section 6: Regulatory and Commercial Landscape

6.1. Regulatory History and Status

The regulatory journey of polyethylene glycol 3350 in the United States reflects its established safety and efficacy, culminating in its widespread availability. The brand MiraLax, manufactured by Braintree Laboratories, Inc., was first approved by the U.S. Food and Drug Administration (FDA) as a prescription-only medication on February 18, 1999, under New Drug Application (NDA) #20-698.[52]

Recognizing its favorable safety profile after years of prescription use, the FDA later approved MiraLax for over-the-counter (OTC) sale on October 6, 2006, under NDA #022015.[53] This landmark decision significantly broadened patient access to the medication for the treatment of occasional constipation.

Today, polyethylene glycol maintains a dual status. It is widely available as an OTC product (e.g., MiraLax and its generic equivalents) for constipation.[9] Concurrently, it remains a prescription product when formulated in high-volume kits with electrolytes for the purpose of bowel preparation.[3] The regulatory landscape also includes actions related to Abbreviated New Drug Applications (ANDAs) for generic prescription versions, indicating ongoing FDA oversight of the market.[54]

6.2. Commercial Formulations and Brand Names

A variety of commercial products containing polyethylene glycol are available, tailored to different clinical needs. The market can be broadly divided into formulations for constipation and those for bowel preparation.

• For Constipation: These products typically contain only PEG 3350 as the active ingredient and are available as powders for reconstitution. Prominent brand names include MiraLax, GlycoLax, ClearLax, GaviLAX, RestoraLAX (in Canada), and Laxido (in the UK).[1] The original developer of MiraLax was Braintree Laboratories, which is now part of Sebela Pharmaceuticals.[52] Numerous other companies, such as Aurohealth LLC, now manufacture generic OTC versions.[58]
• For Bowel Preparation: These are prescription-only kits that combine high-dose PEG 3350 with electrolytes. Major brand names include GoLYTELY, MoviPrep, NuLYTELY, CoLyte, and TriLyte.[1] Braintree Laboratories / Sebela Pharmaceuticals is the manufacturer of GoLYTELY and other prominent bowel prep kits.[57]

The following table provides a practical guide to the commercial landscape.

Table 4: Major Commercial Formulations of Polyethylene Glycol

Brand Name	Manufacturer (Original/Prominent)	Primary Indication	Key Formulation Details
MiraLax	Braintree Labs / Bayer	Constipation	PEG 3350 powder (OTC) 52
GlycoLax	Various (e.g., Martin Ekwealor Pharmaceuticals)	Constipation	PEG 3350 powder (Rx/OTC) 56
ClearLax, GaviLAX	Various generic manufacturers	Constipation	PEG 3350 powder (OTC) 55
RestoraLAX	Bayer	Constipation	PEG 3350 powder (Available in Canada) 1
GoLYTELY	Braintree Labs / Sebela Pharma	Bowel Preparation	PEG 3350 + Electrolytes (Sodium Sulfate, Bicarbonate, Chloride; Potassium Chloride) (Rx) 34
MoviPrep	Salix Pharmaceuticals	Bowel Preparation	PEG 3350 + Electrolytes + Ascorbic Acid/Sodium Ascorbate (Rx) 1
NuLYTELY	Braintree Labs / Sebela Pharma	Bowel Preparation	PEG 3350 + Electrolytes (Sulfate-free formulation) (Rx) 34
CoLyte, TriLyte	Various (e.g., Meda Pharmaceuticals)	Bowel Preparation	PEG 3350 + Electrolytes (Rx) 1
HalfLytely	Braintree Labs	Bowel Preparation	Lower volume (2L) PEG 3350 + Electrolytes, co-packaged with bisacodyl tablets (Rx) 34

Section 7: Broader Applications of the Polyethylene Glycol Polymer

Beyond its role as a laxative, the unique physicochemical properties of the polyethylene glycol polymer have made it an indispensable tool in a vast range of biomedical, industrial, and research applications.

7.1. Biomedical and Pharmaceutical Technology: The Era of PEGylation

One of the most significant applications of PEG in modern medicine is PEGylation, the process of covalently attaching PEG chains to therapeutic molecules, particularly proteins, peptides, and nanoparticles.[5] This strategy is used to overcome common challenges in drug development and delivery. The primary benefits of PEGylation include:

• Improved Pharmacokinetics: By dramatically increasing the hydrodynamic size of a drug molecule, PEGylation significantly reduces its rate of renal clearance through glomerular filtration. This results in a much longer plasma half-life, allowing for less frequent dosing and more sustained therapeutic concentrations.[5]
• Reduced Immunogenicity: The flexible, hydrophilic PEG chains form a protective "shield" around the surface of a protein drug. This masks immunogenic epitopes, making the drug less likely to be recognized and neutralized by the host's immune system.[21] This "stealth" property is critical for the long-term efficacy of many biologic therapies.
• Enhanced Solubility and Stability: PEGylation can improve the aqueous solubility and stability of hydrophobic drugs, making them easier to formulate and administer.[5]

Prominent examples of this technology include PEG-interferon alpha (Pegintron) for hepatitis C, PEG-filgrastim (Neulasta) for neutropenia, and the critical use of PEGylated lipids to form the stable nucleic acid lipid particles (SNALPs) that encapsulate and protect the mRNA in COVID-19 vaccines.[17]

7.2. Industrial, Commercial, and Research Uses

The versatility of PEG extends far beyond the clinic into numerous industrial and consumer sectors:

• Cosmetics and Personal Care: PEG is a workhorse ingredient in the cosmetics industry. Due to its properties as a humectant (retains moisture), surfactant, emulsifier, and cleansing agent, it is found in a vast array of products, including skin creams, personal lubricants, shampoos, and toothpastes.[1]
• Food Industry: Approved as a food additive (E1521 in the EU), PEG is used as an anti-foaming agent in food and drinks, a coating for candies, a binder, and a plasticizer.[1]
• Manufacturing and Industrial Processes: PEG serves diverse roles as a lubricant in metalworking, a binder in the preparation of technical ceramics, a solvent in printers, a heat transfer fluid, and as a chemical intermediate in the production of polyurethanes (used in spandex fibers) and plastics like polyethylene terephthalate (PET).[1]
• Research and Laboratory Applications: In the lab, PEG is used as a crowding agent to mimic cellular conditions in vitro, a precipitating agent for isolating plasmid DNA and crystallizing proteins for X-ray diffraction, and a fusogen to merge cells for creating hybridomas (essential for monoclonal antibody production).[1] It is also used as an internal calibration standard in mass spectrometry.[1]
• Niche and Specialized Applications: The utility of PEG is further demonstrated by its use in unique applications such as the preservation of ancient, waterlogged wooden artifacts like the 17th-century warship Vasa [1], as a component in the solid propellant for Trident II submarine-launched ballistic missiles [1], and as the main ingredient in the "fill" of paintballs.[1]

This ubiquity, however, may have unintended consequences. The constant and widespread exposure of the general population to PEG through cosmetics, foods, and medications could be driving the development of pre-existing anti-PEG antibodies in a subset of individuals. This pre-sensitization is a leading hypothesis to explain the rare but serious hypersensitivity and anaphylactic reactions observed with PEG-containing and PEGylated products.[1] This creates a clinical paradox: the very polymer celebrated for its ability to make drugs less immunogenic can, in some cases, become the target of a significant immune response itself. This highlights a critical area for future research and vigilance in the development and use of PEG-based therapeutics.

Section 8: Conclusion and Future Perspectives

Polyethylene glycol (PEG) is a compound of remarkable duality. In its high-molecular-weight form (PEG 3350), it stands as a highly effective, generally safe, and well-tolerated osmotic laxative, earning a Grade A recommendation as a first-line therapy for chronic constipation and serving as an indispensable agent for procedural bowel preparation. Its pharmacology is elegantly simple: a physical mechanism of water retention in the colon, characterized by minimal systemic absorption and a favorable side-effect profile that distinguishes it from other laxative classes.

Simultaneously, the PEG polymer is a cornerstone of modern pharmaceutical technology. The advent of PEGylation has transformed the development of biologic drugs, enhancing their pharmacokinetic profiles, reducing their immunogenicity, and ultimately improving their clinical utility. This is complemented by its vast range of applications in industrial manufacturing, consumer products, and scientific research, making it one of the most versatile synthetic polymers in use today.

However, its profile is not without complexities and areas requiring further investigation. The unresolved neuropsychiatric safety signal associated with long-term use in pediatric patients underscores the need for continued vigilance and research to understand potential risks in this vulnerable population. Furthermore, the potential for hypersensitivity reactions, possibly driven by widespread environmental exposure, presents a challenge to its reputation as a biologically inert excipient.

Future research, including ongoing Phase 4 clinical trials exploring its use in pre-operative settings and in novel combinations, will continue to refine its clinical applications.[35] The story of polyethylene glycol is a compelling example of how a chemically simple polymer can have complex and profound interactions with biological systems. Continued investigation is essential to fully harness its benefits while mitigating its risks, ensuring its continued value in both medicine and industry.

Works cited

1. Polyethylene glycol - Wikipedia, accessed July 28, 2025, https://en.wikipedia.org/wiki/Polyethylene_glycol
2. Polyethylene Glycol - StatPearls - NCBI Bookshelf, accessed July 28, 2025, https://www.ncbi.nlm.nih.gov/books/NBK557652/
3. Polyethylene Glycol: Package Insert / Prescribing Info - Drugs.com, accessed July 28, 2025, https://www.drugs.com/pro/polyethylene-glycol.html
4. What are the uses of polyethylene glycol (PEG)? - Alfa Chemistry, accessed July 28, 2025, https://www.alfa-chemistry.com/resources/what-are-the-uses-of-polyethylene-glycol-peg.html
5. Understanding the Role and Impact of Poly (Ethylene Glycol) (PEG) on Nanoparticle Formulation: Implications for COVID-19 Vaccines - PubMed Central, accessed July 28, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC9209764/
6. CAS 25322-68-3 Polyethylene glycol - BOC Sciences, accessed July 28, 2025, https://www.bocsci.com/product/polyethylene-glycol-cas-25322-68-3-88594.html
7. Polyethylene glycol: Uses, Interactions, Mechanism of Action | DrugBank Online, accessed July 28, 2025, https://go.drugbank.com/drugs/DB09287
8. CAS Number 25322-68-3 - PCC Group Product Portal, accessed July 28, 2025, https://www.products.pcc.eu/en/cas-numbers/25322-68-3/
9. Polyethylene glycol 3350 (oral route) - Side effects & dosage - Mayo Clinic, accessed July 28, 2025, https://www.mayoclinic.org/drugs-supplements/polyethylene-glycol-3350-oral-route/description/drg-20523233
10. Polyethylene Glycol 3350: MedlinePlus Drug Information, accessed July 28, 2025, https://medlineplus.gov/druginfo/meds/a603032.html
11. Laxatives - NHS, accessed July 28, 2025, https://www.nhs.uk/medicines/laxatives/
12. my.clevelandclinic.org, accessed July 28, 2025, https://my.clevelandclinic.org/health/drugs/18795-polyethylene-glycol-powder-for-solution#:~:text=It%20works%20by%20increasing%20the,group%20of%20medications%20called%20laxatives.
13. Polyethylene Glycol Powder (MiraLax®): Uses & Side Effects - Cleveland Clinic, accessed July 28, 2025, https://my.clevelandclinic.org/health/drugs/18795-polyethylene-glycol-powder-for-solution
14. Comparison of the effectiveness of polyethylene glycol with and, accessed July 28, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC4815254/
15. Safety of polyethylene glycol 3350 solution in chronic constipation ..., accessed July 28, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC4956069/
16. pmc.ncbi.nlm.nih.gov, accessed July 28, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC4815254/#:~:text=Polyethylene%20glycol%20is%20biologically%20inert,gas%20%5B4%2C%205%5D.
17. Polyethylene glycol 400: Uses, Interactions, Mechanism of Action ..., accessed July 28, 2025, https://go.drugbank.com/drugs/DB11077
18. PEGylated Proteins: Evaluation of Their Safety in the Absence of Definitive Metabolism Studies - ResearchGate, accessed July 28, 2025, https://www.researchgate.net/publication/6774009_PEGylated_Proteins_Evaluation_of_Their_Safety_in_the_Absence_of_Definitive_Metabolism_Studies
19. Pharmacokinetics and Bioanalysis of PEGylated Drugs - BOC Sciences, accessed July 28, 2025, https://peg.bocsci.com/resources/pharmacokinetics-and-bioanalysis-of-pegylated-drugs.html
20. Pharmacokinetic and biodistribution properties of poly(ethylene glycol)-protein conjugates | Request PDF - ResearchGate, accessed July 28, 2025, https://www.researchgate.net/publication/9088374_Pharmacokinetic_and_biodistribution_properties_of_polyethylene_glycol-protein_conjugates
21. Modulation of the Pharmacokinetics and Pharmacodynamics of Proteins by Polyethylene Glycol Conjugation - University of Alberta, accessed July 28, 2025, https://sites.ualberta.ca/~csps/JPPS3(1)/R.Mehvar/Glycol.htm
22. Modulation of the Pharmacokinetics and Pharmacodynamics of Proteins by Polyethylene Glycol Conjugation, accessed July 28, 2025, https://digitalcommons.chapman.edu/cgi/viewcontent.cgi?article=1110&context=pharmacy_articles
23. Polyethylene Glycol (PEG-3350, Colyte) Poisoning due to Intra-Peritoneal Leakage in an Elderly Patient - ACC : Acute and Critical Care, accessed July 28, 2025, https://www.accjournal.org/journal/view.php?doi=10.4266/kjccm.2015.30.1.56
24. How Long Does Polyethylene Glycol Stay In Your System? - Chemistry For Everyone, accessed July 28, 2025, https://www.youtube.com/watch?v=uOC7XQu4Ba8
25. Directions - DailyMed, accessed July 28, 2025, https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=bcd57d3c-e1c4-474f-a757-ca89b020278b&type=display
26. Small doses of the unabsorbable substance polyethylene glycol 3350 accelerate oro-caecal transit, but slow gastric emptying in healthy subjects - PubMed, accessed July 28, 2025, https://pubmed.ncbi.nlm.nih.gov/15733521/
27. GoLytely, MiraLax (polyethylene glycol) dosing, indications ..., accessed July 28, 2025, https://reference.medscape.com/drug/golytely-miralax-polyethylene-glycol-342026
28. What is Polyethylene glycol (Miralax) used for? - GoodRx, accessed July 28, 2025, https://www.goodrx.com/miralax/what-is
29. Efficacy and Safety of Over-the-Counter Therapies for Chronic Constipation: An Updated Systematic Review, accessed July 28, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC8191753/
30. Golytely (polyethylene glycol 3350 and electrolytes) oral solution label - accessdata.fda.gov, accessed July 28, 2025, https://www.accessdata.fda.gov/drugsatfda_docs/label/2013/019011s025lbl.pdf
31. These highlights do not include all the information needed to use POLYETHYLENE GLYCOL 3350, SODIUM CHLORIDE, SODIUM BICARBONATE and POTASSIUM CHLORIDE for Oral Solution safely and effectively. See full prescribing information for POLYETHYLENE GLYCOL 3350, SODIUM CHLORIDE, SODIUM BICARBONATE and POTASSIUM CHLORIDE for Oral Solution. POLYETHYLENE GLYCOL 3350, SODIUM CHLORIDE, SODIUM BICARBONATE and POTASSIUM CHLORIDE - DailyMed, accessed July 28, 2025, https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=37c111ec-5b62-42b9-bbb2-3b0c530e34c9
32. PEG-3350, Electrolytes and Ascorbate: Package Insert / Prescribing ..., accessed July 28, 2025, https://www.drugs.com/pro/peg-3350-electrolytes-and-ascorbate.html
33. Polyethylene glycol 3350, electrolytes, and ascorbic acid (oral route) - Side effects & dosage, accessed July 28, 2025, https://www.mayoclinic.org/drugs-supplements/polyethylene-glycol-3350-electrolytes-and-ascorbic-acid-oral-route/description/drg-20068970
34. Polyethylene Glycol 3350: uses, dosing, warnings, adverse events, interactions - MedCentral, accessed July 28, 2025, https://www.medcentral.com/drugs/monograph/17118-382594/polyethylene-glycol-3350-oral
35. Constipation Recruiting Phase 4 Trials for Polyethylene glycol (DB09287) - DrugBank, accessed July 28, 2025, https://go.drugbank.com/indications/DBCOND0004520/clinical_trials/DB09287?phase=4&status=recruiting
36. Bowel Preparation Solutions Unknown Status Phase 4 Trials for Polyethylene glycol (DB09287) | DrugBank Online, accessed July 28, 2025, https://go.drugbank.com/indications/DBCOND0057777/clinical_trials/DB09287?phase=4&status=unknown_status
37. Miralax Dosage Guide for Kids and Adults - GoodRx, accessed July 28, 2025, https://www.goodrx.com/miralax/dosage
38. Safety assessment on polyethylene glycols (PEGs) and their derivatives as used in cosmetic products - ResearchGate, accessed July 28, 2025, https://www.researchgate.net/publication/7732501_Safety_assessment_on_polyethylene_glycols_PEGs_and_their_derivatives_as_used_in_cosmetic_products
39. Polyethylene glycol 3350 and electrolytes (oral route) - Side effects & dosage - Mayo Clinic, accessed July 28, 2025, https://www.mayoclinic.org/drugs-supplements/polyethylene-glycol-3350-and-electrolytes-oral-route/description/drg-20552446
40. MiraLAX interactions: Alcohol, medications, and other factors, accessed July 28, 2025, https://www.medicalnewstoday.com/articles/drugs-miralax-interactions
41. MiraLAX and Interactions: Other Drugs, Supplements, and More - Healthline, accessed July 28, 2025, https://www.healthline.com/health/drugs/miralax-interactions
42. Laxatives - StatPearls - NCBI Bookshelf, accessed July 28, 2025, https://www.ncbi.nlm.nih.gov/books/NBK537246/
43. Bulk-Forming Laxatives: What You Should Know - Healthline, accessed July 28, 2025, https://www.healthline.com/health/digestive-health/bulk-forming-laxatives
44. Laxatives: Types, Purpose, and Side-Effects - Patient.info, accessed July 28, 2025, https://patient.info/digestive-health/constipation/laxatives
45. How to Safely Use Laxatives for Constipation - WebMD, accessed July 28, 2025, https://www.webmd.com/digestive-disorders/laxatives-for-constipation-using-them-safely
46. Laxatives: What They Do, Types & How To Use - Cleveland Clinic, accessed July 28, 2025, https://my.clevelandclinic.org/health/treatments/25121-laxatives
47. Miralax vs Colace: How Do They Compare for Constipation Relief ..., accessed July 28, 2025, https://www.goodrx.com/conditions/constipation/miralax-vs-colace
48. Polyethylene glycol 3350 plus electrolytes for chronic constipation: a 2-week, randomized, double-blind, placebo-controlled study with a 52-week open-label extension - PubMed Central, accessed July 28, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC6698298/
49. The treatment of chronic constipation in adults: a systematic review - NCBI, accessed July 28, 2025, https://www.ncbi.nlm.nih.gov/books/NBK67055/
50. The treatment of chronic constipation in adults. A systematic review - PubMed, accessed July 28, 2025, https://pubmed.ncbi.nlm.nih.gov/9034942/
51. Laxatives for the management of constipation in people receiving palliative care - Candy, B, accessed July 28, 2025, https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD003448.pub4/full
52. Drug Approval Package: MiraLax (Polyethylene Glycol 3350) NDA ..., accessed July 28, 2025, https://www.accessdata.fda.gov/drugsatfda_docs/nda/99/020698.cfm
53. Drug Approval Package: MiraLax (Polyethylene Glycol 3350) NDA #022015 - accessdata.fda.gov, accessed July 28, 2025, https://www.accessdata.fda.gov/drugsatfda_docs/nda/2006/022015s000_toc.cfm
54. Prescription Polyethylene Glycol 3350; Denial of a Hearing and Order Withdrawing Approval of Abbreviated New Drug Applications; Temporary Stay of Effective Date - Federal Register, accessed July 28, 2025, https://www.federalregister.gov/documents/2018/07/30/2018-16148/prescription-polyethylene-glycol-3350-denial-of-a-hearing-and-order-withdrawing-approval-of
55. www.webmd.com, accessed July 28, 2025, https://www.webmd.com/drugs/2/drug-17116/miralax-oral/details
56. Polyethylene glycol 3350 - brand name list from Drugs.com, accessed July 28, 2025, https://www.drugs.com/ingredient/polyethylene-glycol-3350.html
57. Our Products - Sebela Pharmaceuticals, accessed July 28, 2025, https://sebelapharma.com/our-products
58. Label: POLYETHYLENE GLYCOL 3350 powder, for solution - DailyMed, accessed July 28, 2025, https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d3c77f3f-57aa-4e2d-88aa-731cbb22af70&audience=consumer
59. Polyethylene Glycol & Electrolytes: Side Effects, Uses, Dosage, Interactions, Warnings - Rx List, accessed July 28, 2025, https://www.rxlist.com/polyethylene_glycol_and_electrolytes/generic-drug.htm
60. mms.mckesson.com, accessed July 28, 2025, https://mms.mckesson.com/product/257815/Braintree-Labs-52268010001
61. Daily Medication Pearl: Polyethylene Glycol 3350 (Golytely) - Pharmacy Times, accessed July 28, 2025, https://www.pharmacytimes.com/view/daily-medication-pearl-polyethylene-glycol-3350-golytely-
62. Label: POLYETHYLENE GLYCOL 3350 NF PEGYLAX- polyethylene glycol 3350 powder, for solution - DailyMed, accessed July 28, 2025, https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=bcd57d3c-e1c4-474f-a757-ca89b020278b
63. Pharmacodynamics and pharmacokinetics of polyethylene glycol ..., accessed July 28, 2025, https://pubmed.ncbi.nlm.nih.gov/11115081/
64. Uses Of Polyethylene Glycol | The Chemistry Blog - Chemical Suppliers, accessed July 28, 2025, https://www.chemicals.co.uk/blog/uses-of-polyethylene-glycol