- Approval Id
- 951adc5e9c71f03c
- Drug Approval Emc Name
- Melatonin 5mg Hard Capsules
- Drug Name
- Melatonin 5mg Hard Capsules
- Company Name
- Colonis Pharma Ltd
- Company Address
- 25 Bedford Square, Bloomsbury, London, WC1B 3HH
- Company Website
- //www.colonis.co.uk
- Company Medical Info Direct Line
- +44 (0) 1932 555 026
- Company Medical Info Email
- medinfo@colonis.co.uk
- Atc Code
- N05CH01
- Legal Category
- Prescription only medicine
- Authorisation Holder
- Colonis Pharma Ltd
25 Bedford Square,
Bloomsbury,
London,
WC1B 3HH,
United Kingdom
- Authorisation Number
- PL 41344/0060
- Authorisation Date
- 11/06/2025
- Instruction Authorisation Holder
- Colonis Pharma Ltd
25 Bedford Square,
Bloomsbury,
London,
WC1B 3HH,
United Kingdom
- Instruction Authorisation Number
- PL 41344/0060
- Instruction Authorisation Date
- 11/06/2025
- Instruction Composition
- Melatonin 5 mg Hard Capsules
Each 5 mg hard capsule contains 5 mg of melatonin.
Excipient(s) with known effect
Each 5 mg hard capsule contains up to 0.011 mg sodium.
For the full list of excipients, see section 6.1.
- Instruction Dosage Form
- Hard Capsule
Opaque hard gelatin capsules of light blue body and light blue cap (size 1).
- Instruction Clinical Particulars
- 4.1 Therapeutic indications
Melatonin Hard Capsules are indicated for short-term treatment of jet-lag in adults.4.2 Posology and method of administration
\*\*Posology\*\*
The standard dose is 3 mg daily for a maximum of 5 days. The dose may be increased to 5 mg or 6 mg if the standard dose does not adequately alleviate symptoms. The dose that adequately alleviates symptoms should be taken for the shortest period. A lower dose of 2mg may be sufficient for some individuals.
The first dose should be taken on arrival at destination at the habitual bed-time.
Due to the potential for incorrectly timed intake of melatonin to have no effect, or an adverse effect, on re-synchronisation following jet-lag, Melatonin Hard Capsules should not be taken before 20:00 hr or after 04:00 hr at destination.
Food can enhance the increase in plasma melatonin concentration (see Section 5.2). Intake of melatonin with carbohydrate-rich meals may impair blood glucose control for several hours (see Section 4.4). It is recommended that food is not consumed 2 h before and 2 h after intake of Melatonin Hard Capsules.
As alcohol can impair sleep and potentially worsen certain symptoms of jet-lag (e.g. headache, morning fatigue, concentration) it is recommended that alcohol is not consumed when taking Melatonin Hard Capsules.
Melatonin Hard Capsules may be taken for a maximum of 16 treatment periods per year.
\*\*Elderly\*\*
As the pharmacokinetics of melatonin (immediate release) is comparable in young adults and elderly persons in general, no specific dosage recommendations for elderly persons are provided (see Section 5.2).
\*\*Renal impairment\*\*
There is only limited experience regarding the use of Melatonin Hard Capsules in patients with renal impairment. Caution should be exercised if melatonin is used by patients with renal impairment. Melatonin Hard Capsules are not recommended for patients with severe renal impairment (see Section 5.2).
\*\*Hepatic impairment\*\*
There is no experience regarding the use of Melatonin Hard Capsules in patients with hepatic impairment. Limited data indicate that plasma clearance of melatonin is significantly reduced in patients with liver cirrhosis. Melatonin Hard Capsules are not recommended in patients with moderate or severe hepatic impairment (see Section 5.2).
\*\*Paediatric population\*\*
The safety and efficacy of Melatonin Hard Capsules in children and adolescents aged 0 – 18 years have not been established. Melatonin Hard Capsules should not be used in children and adolescents due to safety and efficacy concerns (see Sections 4.4 and 5.1).
Method of administration
For oral use. Capsules should be swallowed whole with fluid.4.3 Contraindications
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.4.4 Special warnings and precautions for use
Melatonin may cause drowsiness. Therefore, the product should be used with caution, if the effects of drowsiness are likely to be associated with a risk to patient safety.
Melatonin may increase seizure frequency in patients experiencing seizures (e.g. epileptic patients). Patients suffering from seizures must be informed about this possibility before using Melatonin Hard Capsules. Melatonin may promote or increase the incidence of seizures in children and adolescents with multiple neurological defects.
Occasional case reports have described exacerbation of an autoimmune disease in patients taking melatonin. There are no data regarding use of Melatonin Hard Capsules in patients with autoimmune diseases. Melatonin Hard Capsules are not recommended in patients with autoimmune diseases.
Limited data suggest that melatonin taken in close proximity to ingestion of carbohydrate-rich meals may impair blood glucose control for several hours. Melatonin Hard Capsules should be taken at least 2 hours before and at least 2 hours after a meal; ideally at least 3 hours after meal by persons with significantly impaired glucose tolerance or diabetes.
Only limited data are available on the safety and efficiency of melatonin in patients with renal impairment or hepatic impairment. Melatonin Hard Capsules are not recommended for use in patients suffering from severe renal impairment or moderate or severe hepatic impairment.
Paediatric population
The safety and efficacy of Melatonin Hard Capsules in children and adolescents aged 0 – 18 years have not been established. Melatonin Hard Capsules should not be used in children and adolescents due to safety and efficacy concerns (see Section 5.1).
\*\*Melatonin 2 mg Hard Capsules and Melatonin 5 mg Hard Capsules contain sodium.\*\*
These medicines contain less than 1 mmol sodium (23 mg) per capsule, that is to say essentially “sodium-free”.4.5 Interaction with other medicinal products and other forms of interaction
Interaction studies have only been performed in adults.
Pharmacokinetic interactions
• Melatonin is metabolised mainly by the hepatic cytochrome P450 CYP1A enzymes, primarily CYP1A2. Therefore, interactions between melatonin and other active substances as a consequence of their effect on CYP1A enzymes are possible.
• Caution is indicated in patients treated with fluvoxamine, since this agent increases melatonin levels (17-fold higher AUC and 12-fold higher serum Cmax) by inhibiting its metabolism via CYP1A2 and CYP2C19. This combination should be avoided.
• Caution is indicated in patients taking 5- or 8-methoxypsoralen (5 or 8- MOP), since this agent increases melatonin levels by inhibiting its metabolism.
• Caution is indicated in patients taking cimetidine, since this agent increases plasma melatonin levels by inhibiting its metabolism by CYP2D.
• Caution should be exercised in patients receiving estrogen therapy (e.g. in the form of contraceptives or hormone replacement therapy), since estrogens increase melatonin level by inhibiting its metabolism, primarily via inhibition of CYP1A2.
• CYP1A2 inhibitors (such as quinolones) may increase systemic melatonin levels.
• CYP1A2 inducers (such as carbamazepine and rifampicin) may reduce plasma concentrations of melatonin.
• Cigarette smoking may decrease melatonin levels due to induction of CYP1A2.
Pharmacodynamic interactions
• Melatonin may enhance the sedative effect of benzodiazepines (e.g. midazolam, temazepam) and non-benzodiazepine hypnotics (e.g. zaleplon, zolpidem, zopiclone). In a study of jet-lag therapy the combination of melatonin and zolpidem resulted in a higher incidence of morning sleepiness, nausea, and confusion, and reduced activity during the first hour after getting up, compared to zolpidem alone.
• Melatonin may affect the anticoagulation activity of warfarin.4.6 Fertility, pregnancy and lactation
\*\*Pregnancy\*\*
There are no or limited amount of data for the use of melatonin in pregnant women.
Exogenous melatonin readily crosses the human placenta.
Animal studies are insufficient with respect to reproductive toxicity (see Section 5.3).
Melatonin Hard Capsules are not recommended during pregnancy or in women of childbearing potential not using contraception.
\*\*Breast-feeding\*\*
There is insufficient data on the excretion of melatonin / metabolites in human milk. Endogenous melatonin is secreted in human milk.
Available pharmacodynamic / toxicological data in animals have shown excretion of melatonin / metabolites milk (see Section 5.3).
A risk to the suckling child cannot be excluded.
Melatonin Hard Capsules should not be used during breast-feeding.
\*\*Fertility\*\*
High doses of melatonin and use for longer periods than indicated may compromise fertility in humans.
Animal studies are insufficient with respect to effects on fertility (see Section 5.3).
Melatonin Hard Capsules are not recommended in women and men planning pregnancy.4.7 Effects on ability to drive and use machines
Melatonin has a moderate influence on the ability to drive and use machines. Melatonin may cause drowsiness and may decrease alertness for several hours, therefore use of Melatonin Hard Capsules is not recommended prior to driving and using machines.4.8 Undesirable effects
\*\*Summary of the safety profile\*\*
Drowsiness / sleepiness, headache, and dizziness / disorientation are the most frequently report adverse effects when melatonin is taken on a short-term basis to treat jet-lag. Drowsiness, headache, dizziness, and nausea are also the adverse effects reported most frequently when typical clinical doses of melatonin have been taken for periods of several days to several weeks by healthy persons and patients.
\*\*Tabulated list adverse reactions\*\*
The following adverse reactions to melatonin in general have been reported in clinical trials or spontaneous case reports. Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness.
| | | | | | |
| --- | --- | --- | --- | --- | --- |
| \*\*System Organ Class\*\* | \*\*Very Common\*\* (≥ 1/10) | \*\*Common\*\* (≥1/100 to <1/10) | \*\*Uncommon\*\* (≥1/1,000 to <1/100) | \*\*Rare\*\* (≥1/10,000 to <1/1,000) | \*\*Not known:\*\* (cannot be established from the available data) |
| Blood and lymphatic system disorders | | | | leucopenia, thrombocytopenia | |
| Immune system disorders | | | | | hypersensitivity reaction |
| Metabolism and nutrition disorders | | | | hypertriglyceridaemia | hyperglycaemia |
| Psychiatric disorders | | | irritability, nervousness, restlessness, abnormal dreams, anxiety | mood altered, aggressive behaviour, disorientation, libido increased | |
| Nervous system disorders | | headache, somnolence | dizziness | syncope (fainting), memory impairment, restless legs syndrome, paraesthesia | |
| Eye disorders | | | | visual acuity reduced, vision blurred, lacrimation increased | |
| Cardiac disorders | | | | palpitations | |
| Vascular disorders | | | hypertension | hot flushes | |
| Gastrointestinal disorders | | | abdominal pain, upper abdominal pain, dyspepsia, oral ulcers, dry mouth, nausea | vomiting, flatulence, salivary hypersecretion, halitosis, gastritis | |
| Skin and subcutaneous tissue disorders | | | pruritus, rash, dry skin | nail disorder | tongue edema, edema of the oral mucosa |
| Musculoskeletal and connective tissue disorders | | | | arthritis, muscle spasms | |
| Renal and urinary disorders | | | glycosuria, proteinuria | polyuria, haematuria | |
| Reproductive system and breast disorders | | | | priapism, prostatitis | galactorrhoea |
| General disorders and administration site conditions | | | chest pain, malaise | thirst | |
| Laboratory and other examinations | | | weight increased | blood electrolytes abnormal | |
\*\*Reporting of suspected adverse reactions\*\*
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via Yellow Card Scheme, Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.4.9 Overdose
Drowsiness, headache, dizziness, and nausea are the most commonly reported signs and symptoms of overdose with oral melatonin.
Ingestion of daily doses of up to 300 mg of melatonin did not cause clinically significant adverse reactions.
Flushes, abdominal cramps, diarrhoea, headache, and scotoma lucidum have been reported after ingestion of extremely high melatonin doses (3000 – 6600 mg) for several weeks.
General supportive measures should be employed. Gastric lavage and administration of activated charcoal can be considered.
Clearance of the active substance is expected within 12 hours of ingestion.
- Instruction Pharmacology
- 5.1 Pharmacodynamic properties
Pharmacotherapeutic group: Melatonin,
ATC code: N05CH01
Melatonin is a hormone and antioxidant. Melatonin secreted by the pineal gland is involved in the synchronisation of circadian rhythms to the diurnal light-dark cycle. Melatonin secretion / plasma melatonin level increases shortly after the onset of darkness, peaks around 02:00 – 04:00 hr and declines to the daytime nadir by dawn. Peak melatonin secretion is almost diametrically opposite peak daylight intensity, with daylight being the primary stimulus for maintaining the circadian rhythmicity of melatonin secretion.
\*\*Mechanism of action\*\*
The pharmacological mechanism of action in melatonin is believed to be based on its interaction with MT1-, MT2- and MT3 receptors, as these receptors (particularly MT1 and MT2) are involved in the regulation of sleep and circadian rhythms in general.
\*\*Pharmacodynamic effects\*\*
Melatonin has a hypnotic / sedative effect and increases propensity for sleep. Melatonin administered earlier or later than the nocturnal peak in melatonin secretion can, respectively, advance or delay the circadian rhythmicity of melatonin secretion. Administration of melatonin at bedtime (between 22:00 and 24:00 hr) at destination following rapid transmeridian travel (aircraft flight) hastens resynchronisation of circadian rhythmicity from 'departure time' to 'destination time', and ameliorates the collection of symptoms known as jet-lag that are a consequence of such de- synchronisation.
\*\*Clinical efficacy and safety\*\*
Typical symptoms of jet-lag are sleep disturbances and daytime tiredness and fatigue, though mild cognitive impairment, irritability, and gastrointestinal disturbances may also occur. Jet-lag is worse the more time-zones crossed, and is typically worse following eastward travel as people generally find it harder to advance their circadian (body clock) than to delay it, as required following westward travel. Clinical trials have found melatonin to reduce patient-assessed overall symptoms of jet-lag by ~ 44%, and to shorten the duration of jet-lag. In 2 studies of flights over 12 time zones melatonin effectively reduce the duration of jet-lag by ~ 33%. Due to the potential for incorrectly timed intake of melatonin to have no effect, or an adverse effect, on re- synchronisation of circadian rhythmicity / jet-lag, melatonin should not be taken before 20:00 hr or after 04:00 hr at destination.
Adverse effects reported in jet-lag studies involving melatonin doses of 0.5 to 8 mg were typically mild, and often difficult to distinguish from symptoms of jet-lag.
Transient drowsiness / sedation, headache, and dizziness / disorientation were reported; these same adverse effects, plus nausea, are those typically associated with short-term use of melatonin in reviews of the safety of melatonin in humans.
\*\*Paediatric population\*\*
The safety and efficacy of melatonin in children and adolescents aged 0 – 18 years have not been established. Melatonin Hard Capsules should not be used in children and adolescents aged 0 – 18 years due to safety concerns. Specifically, this is due to the fact that interference with the function of endogenous melatonin on the development of the hypothalamic-pituitary-gonadal axis cannot be excluded.5.2 Pharmacokinetic properties
Melatonin is a small, amphiphilic molecule (molecular weight 232 g/mol) active in its parent form. Melatonin is synthesised in the human body from tryptophan via serotonin. Small quantities are obtained via diet. Data summarised below are from studies that generally involved healthy men and women, primarily young and middle- aged adults.
\*\*Absorption\*\*
Orally administered melatonin is almost completely absorbed. Oral bioavailability is ~ 15%, owing to first-pass metabolism of ~ 85%. Plasma Tmax is ~ 50 minutes. A 3 mg dose of immediate- release melatonin raises plasma melatonin Cmax to ~ 3400 pg/mL, which is ~ 60-times the nocturnal (endogenous) plasma melatonin Cmax, though both endogenous- and exogenous Cmax show considerable inter-individual variation.
Data on the effect of intake of food at or around the time of intake of melatonin on its pharmacokinetics are limited, though suggest that concomitant food intake may increase absorption almost 2-fold. Food appears to have a limited effect on Tmax for immediate-release melatonin. This is not expected to affect the efficacy or safety of Melatonin Hard Capsules, however, it is recommended that food is not consumed approximately 2 h before and 2 h after intake of melatonin.
\*\*Distribution\*\*
The protein binding of melatonin is approximately 50 – 60%. Melatonin primarily binds to albumin, though also binds alpha1-acid glycoprotein; binding to other plasma proteins is limited. Melatonin rapidly distributes from the plasma into and out of most tissues and organ, and readily crosses the brain-blood barrier. Melatonin readily crosses the placenta. The level in umbilical blood of full-term babies closely correlates with, and is only slightly lower (~ 15 – 35%) than, that of their mother following ingestion of a 3 mg dose.
\*\*Biotransformation\*\*
Melatonin is mainly metabolised by the liver. Experimental data suggest that the cytochrome P450 enzymes CYP1A1 and CYP1A2 are primarily responsible for melatonin metabolism, with CYP2C19 of minor importance. Melatonin is primarily metabolised to 6-hydroxymelatonin (constituting ~ 80 – 90% of melatonin metabolites recovered in the urine). N-acetylserotonin appears to be the primary minor metabolite (constituting ~ 10% of melatonin metabolites recovered in the urine). Melatonin metabolism is very rapid, with plasma 6-hydroxymelatonin level rising within minutes of exogenous melatonin entering the systemic circulation. 6- hydroxymelatonin undergoes sulphate conjugation (~ 70%) and glucuronide conjugation (~ 30%) prior to excretion.
\*\*Elimination\*\*
Plasma elimination half-life (T½) is ~ 45 minutes (normal range ~ 30 – 60 minutes) in healthy adults. Melatonin metabolites are mainly eliminated by the urine, ~ 90% as sulphate and glucuronide conjugates of 6-hydroxymelatonin. Less than ~ 1% of a melatonin dose is excreted unchanged in urine.
\*\*Linearity\*\*
Plasma melatonin Cmax and AUC increase in a directly proportional, linear manner for oral doses of immediate-release melatonin in the range 3 – 6 mg whereas Tmax and plasma T½ remain constant.
\*\*Gender\*\*
Limited data suggest that Cmax and AUC following ingestion of immediate-release melatonin may be higher (potentially roughly double) in women compared to men, however a large variability in the pharmacokinetics is observed. Plasma melatonin half-life does not appear to be significantly different in men and women.
\*\*Special populations\*\*
\*\*Elderly\*\*
Night-time endogenous melatonin plasma concentration is lower in the elderly compared to young adults. Limited data for plasma- Tmax, Cmax, elimination half- life (T½), and AUC following ingestion of immediate-release melatonin do not indicate significant differences between younger adults and elderly persons in general, though the range of values (inter-individual variability) for each parameter tend to be greater in the elderly.
\*\*Hepatic impairment\*\*
Limited data indicate that daytime endogenous blood melatonin concentration is markedly elevated in patients with liver cirrhosis, probably due to reduced clearance (metabolism) of melatonin. Serum T½ for exogenous melatonin in cirrhosis patients was double that of controls in a small study. As the liver is the primary site of melatonin metabolism, hepatic impairment can be expected to result in increased exposure to exogenous melatonin.
\*\*Renal impairment\*\*
Literature data indicate that there is no accumulation of melatonin after repeated dosing (3 mg for 5 – 11 weeks) in patients on stable haemodialysis. However, as melatonin is primarily excreted as metabolites in the urine, plasma levels of melatonin metabolites can be expected increase in patients with more advanced renal impairment.5.3 Preclinical safety data
Non-clinical data reveal no special hazard for humans based on conventional studies of safety pharmacology, single and repeated dose toxicity, mutagenicity, genotoxicity and carcinogenic potential. Effects were observed only at exposures considered sufficiently in excess of the maximum human exposure indicating little relevance to clinical use.
After intra-peritoneal administration of a single, large dose of melatonin to pregnant mice, fetal body-weight and length tended to be lower, possibly due to maternal toxicity. Delay in sexual maturation in male and female offspring of the rat and ground squirrel occurred upon exposure to melatonin during pregnancy and post- partum. These data indicate that exogenous melatonin crosses the placenta and is secreted in milk, and that it may influence the ontogeny and activation of the hypothalamic-pituitary-gonadal axis. As the rat and ground squirrel are seasonal breeders, the implications of these findings for humans uncertain.
- Instruction Pharmaceutical Particulars
- 6.1 List of excipients
Cellulose, Microcrystalline
Povidone K30
Maltodextrin
Magnesium Stearate
\*\*Shell Formulation\*\*
Indigotine – FD&C Blue 2 (including sodium) (E132)
Gelatin
Titanium Dioxide (E 171)6.2 Incompatibilities
Not applicable.6.3 Shelf life
18 months6.4 Special precautions for storage
Store below 25°C.
Keep in the outer carton to protect from light.6.5 Nature and contents of container
Melatonin Hard Capsules are packed in PVC/PVDC/aluminium blisters. Each blister contains 7 or 10 capsules.
Pack sizes: 10, 14, 28, 30 hard capsules.
Not all pack sizes may be marketed.6.6 Special precautions for disposal and other handling
None.
- Instruction Content
- ## Composition
Melatonin 5 mg Hard Capsules
Each 5 mg hard capsule contains 5 mg of melatonin.
Excipient(s) with known effect
Each 5 mg hard capsule contains up to 0.011 mg sodium.
For the full list of excipients, see section 6.1.
## Pharmaceutical Form
Hard Capsule
Opaque hard gelatin capsules of light blue body and light blue cap (size 1).
## Clinical Particulars
4.1 Therapeutic indications
Melatonin Hard Capsules are indicated for short-term treatment of jet-lag in adults.4.2 Posology and method of administration
\*\*Posology\*\*
The standard dose is 3 mg daily for a maximum of 5 days. The dose may be increased to 5 mg or 6 mg if the standard dose does not adequately alleviate symptoms. The dose that adequately alleviates symptoms should be taken for the shortest period. A lower dose of 2mg may be sufficient for some individuals.
The first dose should be taken on arrival at destination at the habitual bed-time.
Due to the potential for incorrectly timed intake of melatonin to have no effect, or an adverse effect, on re-synchronisation following jet-lag, Melatonin Hard Capsules should not be taken before 20:00 hr or after 04:00 hr at destination.
Food can enhance the increase in plasma melatonin concentration (see Section 5.2). Intake of melatonin with carbohydrate-rich meals may impair blood glucose control for several hours (see Section 4.4). It is recommended that food is not consumed 2 h before and 2 h after intake of Melatonin Hard Capsules.
As alcohol can impair sleep and potentially worsen certain symptoms of jet-lag (e.g. headache, morning fatigue, concentration) it is recommended that alcohol is not consumed when taking Melatonin Hard Capsules.
Melatonin Hard Capsules may be taken for a maximum of 16 treatment periods per year.
\*\*Elderly\*\*
As the pharmacokinetics of melatonin (immediate release) is comparable in young adults and elderly persons in general, no specific dosage recommendations for elderly persons are provided (see Section 5.2).
\*\*Renal impairment\*\*
There is only limited experience regarding the use of Melatonin Hard Capsules in patients with renal impairment. Caution should be exercised if melatonin is used by patients with renal impairment. Melatonin Hard Capsules are not recommended for patients with severe renal impairment (see Section 5.2).
\*\*Hepatic impairment\*\*
There is no experience regarding the use of Melatonin Hard Capsules in patients with hepatic impairment. Limited data indicate that plasma clearance of melatonin is significantly reduced in patients with liver cirrhosis. Melatonin Hard Capsules are not recommended in patients with moderate or severe hepatic impairment (see Section 5.2).
\*\*Paediatric population\*\*
The safety and efficacy of Melatonin Hard Capsules in children and adolescents aged 0 – 18 years have not been established. Melatonin Hard Capsules should not be used in children and adolescents due to safety and efficacy concerns (see Sections 4.4 and 5.1).
Method of administration
For oral use. Capsules should be swallowed whole with fluid.4.3 Contraindications
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.4.4 Special warnings and precautions for use
Melatonin may cause drowsiness. Therefore, the product should be used with caution, if the effects of drowsiness are likely to be associated with a risk to patient safety.
Melatonin may increase seizure frequency in patients experiencing seizures (e.g. epileptic patients). Patients suffering from seizures must be informed about this possibility before using Melatonin Hard Capsules. Melatonin may promote or increase the incidence of seizures in children and adolescents with multiple neurological defects.
Occasional case reports have described exacerbation of an autoimmune disease in patients taking melatonin. There are no data regarding use of Melatonin Hard Capsules in patients with autoimmune diseases. Melatonin Hard Capsules are not recommended in patients with autoimmune diseases.
Limited data suggest that melatonin taken in close proximity to ingestion of carbohydrate-rich meals may impair blood glucose control for several hours. Melatonin Hard Capsules should be taken at least 2 hours before and at least 2 hours after a meal; ideally at least 3 hours after meal by persons with significantly impaired glucose tolerance or diabetes.
Only limited data are available on the safety and efficiency of melatonin in patients with renal impairment or hepatic impairment. Melatonin Hard Capsules are not recommended for use in patients suffering from severe renal impairment or moderate or severe hepatic impairment.
Paediatric population
The safety and efficacy of Melatonin Hard Capsules in children and adolescents aged 0 – 18 years have not been established. Melatonin Hard Capsules should not be used in children and adolescents due to safety and efficacy concerns (see Section 5.1).
\*\*Melatonin 2 mg Hard Capsules and Melatonin 5 mg Hard Capsules contain sodium.\*\*
These medicines contain less than 1 mmol sodium (23 mg) per capsule, that is to say essentially “sodium-free”.4.5 Interaction with other medicinal products and other forms of interaction
Interaction studies have only been performed in adults.
Pharmacokinetic interactions
• Melatonin is metabolised mainly by the hepatic cytochrome P450 CYP1A enzymes, primarily CYP1A2. Therefore, interactions between melatonin and other active substances as a consequence of their effect on CYP1A enzymes are possible.
• Caution is indicated in patients treated with fluvoxamine, since this agent increases melatonin levels (17-fold higher AUC and 12-fold higher serum Cmax) by inhibiting its metabolism via CYP1A2 and CYP2C19. This combination should be avoided.
• Caution is indicated in patients taking 5- or 8-methoxypsoralen (5 or 8- MOP), since this agent increases melatonin levels by inhibiting its metabolism.
• Caution is indicated in patients taking cimetidine, since this agent increases plasma melatonin levels by inhibiting its metabolism by CYP2D.
• Caution should be exercised in patients receiving estrogen therapy (e.g. in the form of contraceptives or hormone replacement therapy), since estrogens increase melatonin level by inhibiting its metabolism, primarily via inhibition of CYP1A2.
• CYP1A2 inhibitors (such as quinolones) may increase systemic melatonin levels.
• CYP1A2 inducers (such as carbamazepine and rifampicin) may reduce plasma concentrations of melatonin.
• Cigarette smoking may decrease melatonin levels due to induction of CYP1A2.
Pharmacodynamic interactions
• Melatonin may enhance the sedative effect of benzodiazepines (e.g. midazolam, temazepam) and non-benzodiazepine hypnotics (e.g. zaleplon, zolpidem, zopiclone). In a study of jet-lag therapy the combination of melatonin and zolpidem resulted in a higher incidence of morning sleepiness, nausea, and confusion, and reduced activity during the first hour after getting up, compared to zolpidem alone.
• Melatonin may affect the anticoagulation activity of warfarin.4.6 Fertility, pregnancy and lactation
\*\*Pregnancy\*\*
There are no or limited amount of data for the use of melatonin in pregnant women.
Exogenous melatonin readily crosses the human placenta.
Animal studies are insufficient with respect to reproductive toxicity (see Section 5.3).
Melatonin Hard Capsules are not recommended during pregnancy or in women of childbearing potential not using contraception.
\*\*Breast-feeding\*\*
There is insufficient data on the excretion of melatonin / metabolites in human milk. Endogenous melatonin is secreted in human milk.
Available pharmacodynamic / toxicological data in animals have shown excretion of melatonin / metabolites milk (see Section 5.3).
A risk to the suckling child cannot be excluded.
Melatonin Hard Capsules should not be used during breast-feeding.
\*\*Fertility\*\*
High doses of melatonin and use for longer periods than indicated may compromise fertility in humans.
Animal studies are insufficient with respect to effects on fertility (see Section 5.3).
Melatonin Hard Capsules are not recommended in women and men planning pregnancy.4.7 Effects on ability to drive and use machines
Melatonin has a moderate influence on the ability to drive and use machines. Melatonin may cause drowsiness and may decrease alertness for several hours, therefore use of Melatonin Hard Capsules is not recommended prior to driving and using machines.4.8 Undesirable effects
\*\*Summary of the safety profile\*\*
Drowsiness / sleepiness, headache, and dizziness / disorientation are the most frequently report adverse effects when melatonin is taken on a short-term basis to treat jet-lag. Drowsiness, headache, dizziness, and nausea are also the adverse effects reported most frequently when typical clinical doses of melatonin have been taken for periods of several days to several weeks by healthy persons and patients.
\*\*Tabulated list adverse reactions\*\*
The following adverse reactions to melatonin in general have been reported in clinical trials or spontaneous case reports. Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness.
| | | | | | |
| --- | --- | --- | --- | --- | --- |
| \*\*System Organ Class\*\* | \*\*Very Common\*\* (≥ 1/10) | \*\*Common\*\* (≥1/100 to <1/10) | \*\*Uncommon\*\* (≥1/1,000 to <1/100) | \*\*Rare\*\* (≥1/10,000 to <1/1,000) | \*\*Not known:\*\* (cannot be established from the available data) |
| Blood and lymphatic system disorders | | | | leucopenia, thrombocytopenia | |
| Immune system disorders | | | | | hypersensitivity reaction |
| Metabolism and nutrition disorders | | | | hypertriglyceridaemia | hyperglycaemia |
| Psychiatric disorders | | | irritability, nervousness, restlessness, abnormal dreams, anxiety | mood altered, aggressive behaviour, disorientation, libido increased | |
| Nervous system disorders | | headache, somnolence | dizziness | syncope (fainting), memory impairment, restless legs syndrome, paraesthesia | |
| Eye disorders | | | | visual acuity reduced, vision blurred, lacrimation increased | |
| Cardiac disorders | | | | palpitations | |
| Vascular disorders | | | hypertension | hot flushes | |
| Gastrointestinal disorders | | | abdominal pain, upper abdominal pain, dyspepsia, oral ulcers, dry mouth, nausea | vomiting, flatulence, salivary hypersecretion, halitosis, gastritis | |
| Skin and subcutaneous tissue disorders | | | pruritus, rash, dry skin | nail disorder | tongue edema, edema of the oral mucosa |
| Musculoskeletal and connective tissue disorders | | | | arthritis, muscle spasms | |
| Renal and urinary disorders | | | glycosuria, proteinuria | polyuria, haematuria | |
| Reproductive system and breast disorders | | | | priapism, prostatitis | galactorrhoea |
| General disorders and administration site conditions | | | chest pain, malaise | thirst | |
| Laboratory and other examinations | | | weight increased | blood electrolytes abnormal | |
\*\*Reporting of suspected adverse reactions\*\*
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via Yellow Card Scheme, Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.4.9 Overdose
Drowsiness, headache, dizziness, and nausea are the most commonly reported signs and symptoms of overdose with oral melatonin.
Ingestion of daily doses of up to 300 mg of melatonin did not cause clinically significant adverse reactions.
Flushes, abdominal cramps, diarrhoea, headache, and scotoma lucidum have been reported after ingestion of extremely high melatonin doses (3000 – 6600 mg) for several weeks.
General supportive measures should be employed. Gastric lavage and administration of activated charcoal can be considered.
Clearance of the active substance is expected within 12 hours of ingestion.
## Pharmacological Properties
5.1 Pharmacodynamic properties
Pharmacotherapeutic group: Melatonin,
ATC code: N05CH01
Melatonin is a hormone and antioxidant. Melatonin secreted by the pineal gland is involved in the synchronisation of circadian rhythms to the diurnal light-dark cycle. Melatonin secretion / plasma melatonin level increases shortly after the onset of darkness, peaks around 02:00 – 04:00 hr and declines to the daytime nadir by dawn. Peak melatonin secretion is almost diametrically opposite peak daylight intensity, with daylight being the primary stimulus for maintaining the circadian rhythmicity of melatonin secretion.
\*\*Mechanism of action\*\*
The pharmacological mechanism of action in melatonin is believed to be based on its interaction with MT1-, MT2- and MT3 receptors, as these receptors (particularly MT1 and MT2) are involved in the regulation of sleep and circadian rhythms in general.
\*\*Pharmacodynamic effects\*\*
Melatonin has a hypnotic / sedative effect and increases propensity for sleep. Melatonin administered earlier or later than the nocturnal peak in melatonin secretion can, respectively, advance or delay the circadian rhythmicity of melatonin secretion. Administration of melatonin at bedtime (between 22:00 and 24:00 hr) at destination following rapid transmeridian travel (aircraft flight) hastens resynchronisation of circadian rhythmicity from 'departure time' to 'destination time', and ameliorates the collection of symptoms known as jet-lag that are a consequence of such de- synchronisation.
\*\*Clinical efficacy and safety\*\*
Typical symptoms of jet-lag are sleep disturbances and daytime tiredness and fatigue, though mild cognitive impairment, irritability, and gastrointestinal disturbances may also occur. Jet-lag is worse the more time-zones crossed, and is typically worse following eastward travel as people generally find it harder to advance their circadian (body clock) than to delay it, as required following westward travel. Clinical trials have found melatonin to reduce patient-assessed overall symptoms of jet-lag by ~ 44%, and to shorten the duration of jet-lag. In 2 studies of flights over 12 time zones melatonin effectively reduce the duration of jet-lag by ~ 33%. Due to the potential for incorrectly timed intake of melatonin to have no effect, or an adverse effect, on re- synchronisation of circadian rhythmicity / jet-lag, melatonin should not be taken before 20:00 hr or after 04:00 hr at destination.
Adverse effects reported in jet-lag studies involving melatonin doses of 0.5 to 8 mg were typically mild, and often difficult to distinguish from symptoms of jet-lag.
Transient drowsiness / sedation, headache, and dizziness / disorientation were reported; these same adverse effects, plus nausea, are those typically associated with short-term use of melatonin in reviews of the safety of melatonin in humans.
\*\*Paediatric population\*\*
The safety and efficacy of melatonin in children and adolescents aged 0 – 18 years have not been established. Melatonin Hard Capsules should not be used in children and adolescents aged 0 – 18 years due to safety concerns. Specifically, this is due to the fact that interference with the function of endogenous melatonin on the development of the hypothalamic-pituitary-gonadal axis cannot be excluded.5.2 Pharmacokinetic properties
Melatonin is a small, amphiphilic molecule (molecular weight 232 g/mol) active in its parent form. Melatonin is synthesised in the human body from tryptophan via serotonin. Small quantities are obtained via diet. Data summarised below are from studies that generally involved healthy men and women, primarily young and middle- aged adults.
\*\*Absorption\*\*
Orally administered melatonin is almost completely absorbed. Oral bioavailability is ~ 15%, owing to first-pass metabolism of ~ 85%. Plasma Tmax is ~ 50 minutes. A 3 mg dose of immediate- release melatonin raises plasma melatonin Cmax to ~ 3400 pg/mL, which is ~ 60-times the nocturnal (endogenous) plasma melatonin Cmax, though both endogenous- and exogenous Cmax show considerable inter-individual variation.
Data on the effect of intake of food at or around the time of intake of melatonin on its pharmacokinetics are limited, though suggest that concomitant food intake may increase absorption almost 2-fold. Food appears to have a limited effect on Tmax for immediate-release melatonin. This is not expected to affect the efficacy or safety of Melatonin Hard Capsules, however, it is recommended that food is not consumed approximately 2 h before and 2 h after intake of melatonin.
\*\*Distribution\*\*
The protein binding of melatonin is approximately 50 – 60%. Melatonin primarily binds to albumin, though also binds alpha1-acid glycoprotein; binding to other plasma proteins is limited. Melatonin rapidly distributes from the plasma into and out of most tissues and organ, and readily crosses the brain-blood barrier. Melatonin readily crosses the placenta. The level in umbilical blood of full-term babies closely correlates with, and is only slightly lower (~ 15 – 35%) than, that of their mother following ingestion of a 3 mg dose.
\*\*Biotransformation\*\*
Melatonin is mainly metabolised by the liver. Experimental data suggest that the cytochrome P450 enzymes CYP1A1 and CYP1A2 are primarily responsible for melatonin metabolism, with CYP2C19 of minor importance. Melatonin is primarily metabolised to 6-hydroxymelatonin (constituting ~ 80 – 90% of melatonin metabolites recovered in the urine). N-acetylserotonin appears to be the primary minor metabolite (constituting ~ 10% of melatonin metabolites recovered in the urine). Melatonin metabolism is very rapid, with plasma 6-hydroxymelatonin level rising within minutes of exogenous melatonin entering the systemic circulation. 6- hydroxymelatonin undergoes sulphate conjugation (~ 70%) and glucuronide conjugation (~ 30%) prior to excretion.
\*\*Elimination\*\*
Plasma elimination half-life (T½) is ~ 45 minutes (normal range ~ 30 – 60 minutes) in healthy adults. Melatonin metabolites are mainly eliminated by the urine, ~ 90% as sulphate and glucuronide conjugates of 6-hydroxymelatonin. Less than ~ 1% of a melatonin dose is excreted unchanged in urine.
\*\*Linearity\*\*
Plasma melatonin Cmax and AUC increase in a directly proportional, linear manner for oral doses of immediate-release melatonin in the range 3 – 6 mg whereas Tmax and plasma T½ remain constant.
\*\*Gender\*\*
Limited data suggest that Cmax and AUC following ingestion of immediate-release melatonin may be higher (potentially roughly double) in women compared to men, however a large variability in the pharmacokinetics is observed. Plasma melatonin half-life does not appear to be significantly different in men and women.
\*\*Special populations\*\*
\*\*Elderly\*\*
Night-time endogenous melatonin plasma concentration is lower in the elderly compared to young adults. Limited data for plasma- Tmax, Cmax, elimination half- life (T½), and AUC following ingestion of immediate-release melatonin do not indicate significant differences between younger adults and elderly persons in general, though the range of values (inter-individual variability) for each parameter tend to be greater in the elderly.
\*\*Hepatic impairment\*\*
Limited data indicate that daytime endogenous blood melatonin concentration is markedly elevated in patients with liver cirrhosis, probably due to reduced clearance (metabolism) of melatonin. Serum T½ for exogenous melatonin in cirrhosis patients was double that of controls in a small study. As the liver is the primary site of melatonin metabolism, hepatic impairment can be expected to result in increased exposure to exogenous melatonin.
\*\*Renal impairment\*\*
Literature data indicate that there is no accumulation of melatonin after repeated dosing (3 mg for 5 – 11 weeks) in patients on stable haemodialysis. However, as melatonin is primarily excreted as metabolites in the urine, plasma levels of melatonin metabolites can be expected increase in patients with more advanced renal impairment.5.3 Preclinical safety data
Non-clinical data reveal no special hazard for humans based on conventional studies of safety pharmacology, single and repeated dose toxicity, mutagenicity, genotoxicity and carcinogenic potential. Effects were observed only at exposures considered sufficiently in excess of the maximum human exposure indicating little relevance to clinical use.
After intra-peritoneal administration of a single, large dose of melatonin to pregnant mice, fetal body-weight and length tended to be lower, possibly due to maternal toxicity. Delay in sexual maturation in male and female offspring of the rat and ground squirrel occurred upon exposure to melatonin during pregnancy and post- partum. These data indicate that exogenous melatonin crosses the placenta and is secreted in milk, and that it may influence the ontogeny and activation of the hypothalamic-pituitary-gonadal axis. As the rat and ground squirrel are seasonal breeders, the implications of these findings for humans uncertain.
## Pharmaceutical Particulars
6.1 List of excipients
Cellulose, Microcrystalline
Povidone K30
Maltodextrin
Magnesium Stearate
\*\*Shell Formulation\*\*
Indigotine – FD&C Blue 2 (including sodium) (E132)
Gelatin
Titanium Dioxide (E 171)6.2 Incompatibilities
Not applicable.6.3 Shelf life
18 months6.4 Special precautions for storage
Store below 25°C.
Keep in the outer carton to protect from light.6.5 Nature and contents of container
Melatonin Hard Capsules are packed in PVC/PVDC/aluminium blisters. Each blister contains 7 or 10 capsules.
Pack sizes: 10, 14, 28, 30 hard capsules.
Not all pack sizes may be marketed.6.6 Special precautions for disposal and other handling
None.
