6 ADVERSE REACTIONS

The following serious adverse reactions are discussed in more detail below and elsewhere in the labeling:

• Hypoglycemia [see Warnings and Precautions (5.1)]
• Hemolytic anemia [see Warnings and Precautions (5.3)]

6.1 Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Approximately 2,800 patients with type 2 diabetes have been treated with glimepiride in the controlled clinical trials. In these trials, approximately 1,700 patients were treated with glimepiride for at least 1 year. In clinical trials, the most common adverse reactions with glimepiride were hypoglycemia, dizziness, asthenia, headache, and nausea.

Table 1 summarizes adverse events, other than hypoglycemia, that were reported in 11 pooled placebo-controlled trials, whether or not considered to be possibly or probably related to study medication. Treatment duration ranged from 13 weeks to 12 months. Terms that are reported represent those that occurred at an incidence of ≥5% among glimepiride-treated patients and more commonly than in patients who received placebo.

Table 1: Eleven Pooled Placebo-Controlled Trials ranging from 13 weeks to 12 months: Adverse Events (excluding hypoglycemia) Occurring in ≥5% of Glimepiride-treated Patients and at a Greater Incidence than with Placebo*

	Glimepiride N=745 %	Placebo N=294 %
Headache	8.2	7.8
Accidental Injury†	5.8	3.4
Flu Syndrome	5.4	4.4
Nausea	5	3.4
Dizziness	5	2.4

• Glimepiride doses ranged from 1 to 16 mg administered daily

† Insufficient information to determine whether any of the accidental injury events were associated with hypoglycemia

Hypoglycemia

In a randomized, double-blind, placebo-controlled monotherapy trial of 14 weeks duration, patients already on sulfonylurea therapy underwent a 3-week washout period then were randomized to glimepiride 1 mg, 4 mg, 8 mg, or placebo. Patients randomized to glimepiride 4 mg or 8 mg underwent forced- titration from an initial dose of 1 mg to these final doses, as tolerated [see Clinical Studies (14.1)]. The overall incidence of possible hypoglycemia (defined by the presence of at least one symptom that the investigator believed might be related to hypoglycemia; a concurrent glucose measurement was not required) was 4% for glimepiride 1 mg, 17% for glimepiride 4 mg, 16% for glimepiride 8 mg and 0% for placebo. All of these events were self- treated.

In a randomized, double-blind, placebo-controlled monotherapy trial of 22 weeks duration, patients received a starting dose of either 1 mg glimepiride or placebo daily. The dose of glimepiride was titrated to a target fasting plasma glucose of 90 to 150 mg/dL. Final daily doses of glimepiride were 1, 2, 3, 4, 6, or 8 mg [see Clinical Studies (14.1)]. The overall incidence of possible hypoglycemia (as defined above for the 14-week trial) for glimepiride vs. placebo was 19.7% vs. 3.2%. All of these events were self-treated.

Weight gain

Glimepiride, like all sulfonylureas, can cause weight gain [see Clinical Studies (14.1)].

Allergic Reactions

In clinical trials, allergic reactions, such as pruritus, erythema, urticaria, and morbilliform or maculopapular eruptions, occurred in less than 1% of glimepiride-treated patients. These may resolve despite continued treatment with glimepiride. There are postmarketing reports of more serious allergic reactions (e.g., dyspnea, hypotension, shock) [see Warnings and Precautions (5.2)].

Laboratory Tests

Elevated serum alanine aminotransferase (ALT)

In 11 pooled placebo-controlled trials of glimepiride, 1.9% of glimepiride- treated patients and 0.8% of placebo-treated patients developed serum ALT greater than 2 times the upper limit of the reference range.

6.2 Postmarketing Experience

The following adverse reactions have been identified during postapproval use of glimepiride. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

• Serious hypersensitivity reactions, including anaphylaxis, angioedema, and Stevens-Johnson syndrome [see Warnings and Precautions (5.2)]
• Hemolytic anemia in patients with and without G6PD deficiency [see Warnings and Precautions (5.3)]
• Impairment of liver function (e.g., with cholestasis and jaundice), as well as hepatitis, which may progress to liver failure
• Porphyria cutanea tarda, photosensitivity reactions and allergic vasculitis
• Leukopenia, agranulocytosis, aplastic anemia, and pancytopenia
• Thrombocytopenia (including severe cases with platelet count less than 10,000/µL) and thrombocytopenic purpura
• Hepatic porphyria reactions and disulfiram-like reactions
• Hyponatremia and syndrome of inappropriate antidiuretic hormone secretion (SIADH), most often in patients who are on other medications or who have medical conditions known to cause hyponatremia or increase release of antidiuretic hormone
• Dysgeusia
• Alopecia

8 USE IN SPECIFIC POPULATIONS

8.1 Pregnancy

Risk Summary

Available data from a small number of published studies and postmarketing experience with glimepiride use in pregnancy over decades have not identified any drug associated risks for major birth defects, miscarriage, or adverse maternal outcomes. However, sulfonylureas (including glimepiride) cross the placenta and have been associated with neonatal adverse reactions such as hypoglycemia. Therefore, glimepiride should be discontinued at least two weeks before expected delivery (see Clinical Considerations). Poorly controlled diabetes in pregnancy is also associated with risks to the mother and fetus (see Clinical Considerations). In animal studies (see Data), there were no effects on embryo-fetal development following administration of glimepiride to pregnant rats and rabbits at oral doses approximately 4000 times and 60 times the maximum human dose based on body surface area, respectively. However, fetotoxicity was observed in rats and rabbits at doses 50 times and 0.1 times the maximum human dose, respectively.

The estimated background risk of major birth defects is 6% to 10% in women with pre-gestational diabetes with a HbA1c >7% and has been reported to be as high as 20% to 25% in women with a HbA1c >10%. The estimated background risk of miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Clinical Considerations

Disease-associated maternal and/or embryo-fetal risk

Poorly controlled diabetes in pregnancy increases the maternal risk for diabetic ketoacidosis, preeclampsia, spontaneous abortions, preterm delivery, and delivery complications. Poorly controlled diabetes increases the fetal risk for major birth defects, still birth, and macrosomia-related morbidity.

Fetal/neonatal adverse reactions

Neonates of women with gestational diabetes who are treated with sulfonylureas during pregnancy may be at increased risk for neonatal intensive care admission and may develop respiratory distress, hypoglycemia, birth injury, and be large for gestational age. Prolonged severe hypoglycemia, lasting 4 to 10 days, has been reported in neonates born to mothers receiving a sulfonylurea at the time of delivery and has been reported with the use of agents with a prolonged half-life. Observe newborns for symptoms of hypoglycemia and respiratory distress and manage accordingly.

Dose adjustments during pregnancy and the postpartum period

Due to reports of prolonged severe hypoglycemia in neonates born to mothers receiving a sulfonylurea at the time of delivery, glimepiride should be discontinued at least two weeks before expected delivery (see Fetal/Neonatal Adverse Reactions).

Data

Animal data

In animal studies, there was no increase in congenital anomalies, but an increase in fetal deaths occurred in rats and rabbits at glimepiride doses 50 times (rats) and 0.1 times (rabbits) the maximum recommended human dose (based on body surface area). This fetotoxicity was observed only at doses inducing maternal hypoglycemia and is believed to be directly related to the pharmacologic (hypoglycemic) action of glimepiride, as has been similarly noted with other sulfonylureas.

8.2 Lactation

Risk Summary

Breastfed infants of lactating women using glimepiride should be monitored for symptoms of hypoglycemia (see Clinical Considerations). It is not known whether glimepiride is excreted in human milk and there are no data on the effects of glimepiride on milk production. Glimepiride is present in rat milk [see Data]. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for glimepiride and any potential adverse effects on the breastfed child from glimepiride or from the underlying maternal condition.

Clinical Considerations

Monitoring for adverse reactions

Monitor breastfed infants for signs of hypoglycemia (e.g., jitters, cyanosis, apnea, hypothermia, excessive sleepiness, poor feeding, seizures).

Data

During prenatal and postnatal studies in rats, significant concentrations of glimepiride were present in breast milk and the serum of the pups. Offspring of rats exposed to high levels of glimepiride during pregnancy and lactation developed skeletal deformities consisting of shortening, thickening, and bending of the humerus during the postnatal period. These skeletal deformations were determined to be the result of nursing from mothers exposed to glimepiride.

8.4 Pediatric Use

The pharmacokinetics, efficacy and safety of glimepiride have been evaluated in pediatric patients with type 2 diabetes as described below. Glimepiride is not recommended in pediatric patients because of its adverse effects on body weight and hypoglycemia.

The pharmacokinetics of a 1 mg single dose of glimepiride was evaluated in 30 patients with type 2 diabetes (male=7; female=23) between ages 10 and 17 years. The mean (± SD) AUC(0-last) (339±203 ng•hr/mL), Cmax (102±48 ng/mL) and t1/2 (3.1±1.7 hours) for glimepiride were comparable to historical data from adults (AUC(0-last) 315±96 ng•hr/mL, Cmax 103±34 ng/mL, and t1/2 5.3±4.1 hours).

The safety and efficacy of glimepiride in pediatric patients was evaluated in a single-blind, 24-week trial that randomized 272 patients (8 to 17 years of age) with type 2 diabetes to glimepiride (n=135) or metformin (n=137). Both treatment-naive patients (those treated with only diet and exercise for at least 2 weeks prior to randomization) and previously treated patients (those previously treated or currently treated with other oral antidiabetic medications for at least 3 months) were eligible to participate. Patients who were receiving oral antidiabetic agents at the time of study entry discontinued these medications before randomization without a washout period. Glimepiride was initiated at 1 mg, and then titrated up to 2, 4, or 8 mg (mean last dose 4 mg) through Week 12, targeting a self-monitored fasting fingerstick blood glucose <126 mg/dL. Metformin was initiated at 500 mg twice daily and titrated at Week 12 up to 1000 mg twice daily (mean last dose 1365 mg).

After 24 weeks, the overall mean treatment difference in HbA1c between glimepiride and metformin was 0.2%, favoring metformin (95% confidence interval -0.3% to +0.6%). Based on these results, the trial did not meet its primary objective of showing a similar reduction in HbA1c with glimepiride compared to metformin.

Table 2: Change from Baseline in HbA1C and Body Weight in Pediatric Patients Taking Glimepiride or Metformin

	Metformin	Glimepiride
Intent-to-treat population using last-observation-carried-forward for missing data (glimepiride, n=127; metformin, n=126) † adjusted for baseline HbA1C and Tanner Stage ‡ Difference is glimepiride – metformin with positive differences favoring metformin
Treatment-Naive Patients*	N=69	N=72
HbA1C (%)
Baseline (mean)	8.2	8.3
Change from baseline (adjusted LS mean)†	-1.2	-1
Adjusted Treatment Difference‡ (95%CI)	0.2 (-0.3; 0.6)
Previously Treated Patients*	N=57	N=55
HbA1C (%)
Baseline (mean)	9	8.7
Change from baseline (adjusted LS mean)†	-0.2	0.2
Adjusted Treatment Difference‡ (95%CI)	0.4 (-0.4; 1.2)
Body Weight (kg)*	N=126	N=129
Baseline (mean)	67.3	66.5
Change from baseline (adjusted LS mean)†	0.7	2
Adjusted Treatment Difference‡ (95% CI)	1.3 (0.3; 2.3)

The profile of adverse reactions in pediatric patients treated with glimepiride was similar to that observed in adults [see Adverse Reactions (6)].

Hypoglycemic events documented by blood glucose values <36 mg/dL were observed in 4% of pediatric patients treated with glimepiride and in 1% of pediatric patients treated with metformin. One patient in each treatment group experienced a severe hypoglycemic episode (severity was determined by the investigator based on observed signs and symptoms).

8.5 Geriatric Use

In clinical trials of glimepiride, 1053 of 3491 patients (30%) were >65 years of age. No overall differences in safety or effectiveness were observed between these patients and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

There were no significant differences in glimepiride pharmacokinetics between patients with type 2 diabetes ≤65 years (n=49) and those >65 years (n=42) [see Clinical Pharmacology (12.3)].

Glimepiride is substantially excreted by the kidney. Elderly patients are more likely to have renal impairment. In addition, hypoglycemia may be difficult to recognize in the elderly [see Dosage and Administration (2.1) and Warnings and Precautions (5.1)]. Use caution when initiating glimepiride and increasing the dose of glimepiride in this patient population.

8.6 Renal Impairment

To minimize the risk of hypoglycemia, the recommended starting dose of glimepiride is 1 mg daily for all patients with type 2 diabetes and renal impairment [see Dosage and Administration (2.1) and Warnings and Precautions (5.1)].

A multiple-dose titration study was conducted in 16 patients with type 2 diabetes and renal impairment using doses ranging from 1 mg to 8 mg daily for 3 months. Baseline creatinine clearance ranged from 10 to 60 mL/min. The pharmacokinetics of glimepiride was evaluated in the multiple-dose titration study and the results were consistent with those observed in patients enrolled in a single-dose study. In both studies, the relative total clearance of glimepiride increased when kidney function was impaired. Both studies also demonstrated that the elimination of the two major metabolites was reduced in patients with renal impairment [see Clinical Pharmacology (12.3)].

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Glimepiride primarily lowers blood glucose by stimulating the release of insulin from pancreatic beta cells. Sulfonylureas bind to the sulfonylurea receptor in the pancreatic beta-cell plasma membrane, leading to closure of the ATP-sensitive potassium channel, thereby stimulating the release of insulin.

12.2 Pharmacodynamics

In healthy subjects, the time to reach maximal effect (minimum blood glucose concentrations) was approximately 2 to 3 hours after single oral doses of glimepiride. The effects of glimepiride on HbA1c, fasting plasma glucose, and postprandial glucose have been assessed in clinical trials [see Clinical Studies (14)].

12.3 Pharmacokinetics

Absorption

Studies with single oral doses of glimepiride in healthy subjects and with multiple oral doses in patients with type 2 diabetes showed peak drug concentrations (Cmax) 2 to 3 hours postdose. When glimepiride was given with meals, the mean Cmax and AUC (area under the curve) were decreased by 8% and 9%, respectively.

Glimepiride does not accumulate in serum following multiple dosing. The pharmacokinetics of glimepiride does not differ between healthy subjects and patients with type 2 diabetes. Clearance of glimepiride after oral administration does not change over the 1 mg to 8 mg dose range, indicating linear pharmacokinetics.

In healthy subjects, the intraindividual and interindividual variabilities of glimepiride pharmacokinetic parameters were 15% to 23% and 24% to 29%, respectively.

Distribution

After intravenous dosing in healthy subjects, the volume of distribution (Vd) was 8.8 L (113 mL/kg), and the total body clearance (CL) was 47.8 mL/min. Protein binding was greater than 99.5%.

Metabolism

Glimepiride is completely metabolized by oxidative biotransformation after either an intravenous or oral dose. The major metabolites are the cyclohexyl hydroxy methyl derivative (M1) and the carboxyl derivative (M2). Cytochrome P450 2C9 is involved in the biotransformation of glimepiride to M1. M1 is further metabolized to M2 by one or several cytosolic enzymes. M2 is inactive. In animals, M1 possesses about one-third of the pharmacological activity of glimepiride, but it is unclear whether M1 results in clinically meaningful effects on blood glucose in humans.

Excretion

When 14C-glimepiride was given orally to 3 healthy male subjects, approximately 60% of the total radioactivity was recovered in the urine in 7 days. M1 and M2 accounted for 80% to 90% of the radioactivity recovered in the urine. The ratio of M1 to M2 in the urine was approximately 3:2 in two subjects and 4:1 in one subject. Approximately 40% of the total radioactivity was recovered in feces. M1 and M2 accounted for about 70% (ratio of M1 to M2 was 1:3) of the radioactivity recovered in feces. No parent drug was recovered from urine or feces. After intravenous dosing in patients, no significant biliary excretion of glimepiride or its M1 metabolite was observed.

Specific Populations

Geriatric patients

A comparison of glimepiride pharmacokinetics in patients with type 2 diabetes ≤65 years and those >65 years was evaluated in a multiple-dose study using glimepiride 6 mg daily. There were no significant differences in glimepiride pharmacokinetics between the two age groups. The mean AUC at steady state for the older patients was approximately 13% lower than that for the younger patients; the mean weight-adjusted clearance for the older patients was approximately 11% higher than that for the younger patients.

Gender

There were no differences between males and females in the pharmacokinetics of glimepiride when adjustment was made for differences in body weight.

Race

No studies have been conducted to assess the effects of race on glimepiride pharmacokinetics but in placebo-controlled trials of glimepiride in patients with type 2 diabetes, the reduction in HbA1C was comparable in Caucasians (n=536), blacks (n=63), and Hispanics (n=63).

Renal impairment

In a single-dose, open-label study, glimepiride 3 mg was administered to patients with mild, moderate and severe renal impairment as estimated by creatinine clearance (CLcr): Group I consisted of 5 patients with mild renal impairment (CLcr >50 mL/min), Group II consisted of 3 patients with moderate renal impairment (CLcr=20 to 50 mL/min) and Group III consisted of 7 patients with severe renal impairment (CLcr <20 mL/min). Although glimepiride serum concentrations decreased with decreasing renal function, Group III had a 2.3-fold higher mean AUC for M1 and an 8.6-fold higher mean AUC for M2 compared to corresponding mean AUCs in Group I. The apparent terminal half- life (T1/2) for glimepiride did not change, while the half-lives for M1 and M2 increased as renal function decreased. Mean urinary excretion of M1 plus M2 as a percentage of dose decreased from 44.4% for Group I to 21.9% for Group II and 9.3% for Group III.

Hepatic impairment

It is unknown whether there is an effect of hepatic impairment on glimepiride pharmacokinetics because the pharmacokinetics of glimepiride has not been adequately evaluated in patients with hepatic impairment.

Obese patients

The pharmacokinetics of glimepiride and its metabolites were measured in a single-dose study involving 28 patients with type 2 diabetes who either had normal body weight or were morbidly obese. While the tmax, clearance and volume of distribution of glimepiride in the morbidly obese patients were similar to those in the normal weight group, the morbidly obese had lower Cmax and AUC than those of normal body weight. The mean Cmax, AUC0-24, AUC0-∞ values of glimepiride in normal vs. morbidly obese patients were 547±218 ng/mL vs. 410±124 ng/mL, 3210±1030 hours·ng/mL vs. 2820±1110 hours·ng/mL and 4000±1320 hours·ng/mL vs. 3280±1360 hours·ng/mL, respectively.

Drug Interactions

Aspirin
In a randomized, double-blind, two-period, crossover study, healthy subjects were given either placebo or aspirin 1 gram three times daily for a total treatment period of 5 days. On Day 4 of each study period, a single 1 mg dose of glimepiride was administered. The glimepiride doses were separated by a 14-day washout period. Coadministration of aspirin and glimepiride resulted in a 34% decrease in the mean glimepiride AUC and a 4% decrease in the mean glimepiride Cmax.

Colesevelam

Concomitant administration of colesevelam and glimepiride resulted in reductions in glimepiride AUC0-∞ and Cmax of 18% and 8%, respectively. When glimepiride was administered 4 hours prior to colesevelam, there was no significant change in glimepiride AUC0-∞ or Cmax, -6% and 3%, respectively [see Dosage and Administration (2.1) and Drug Interactions (7.4)].

Cimetidine and ranitidine

In a randomized, open-label, 3-way crossover study, healthy subjects received either a single 4 mg dose of glimepiride alone, glimepiride with ranitidine (150 mg twice daily for 4 days; glimepiride was administered on Day 3), or glimepiride with cimetidine (800 mg daily for 4 days; glimepiride was administered on Day 3). Coadministration of cimetidine or ranitidine with a single 4 mg oral dose of glimepiride did not significantly alter the absorption and disposition of glimepiride.

Propranolol
In a randomized, double-blind, two-period, crossover study, healthy subjects were given either placebo or propranolol 40 mg three times daily for a total treatment period of 5 days. On Day 4 of each study period, a single 2 mg dose of glimepiride was administered. The glimepiride doses were separated by a 14-day washout period. Concomitant administration of propranolol and glimepiride significantly increased glimepiride Cmax, AUC, and T1/2 by 23%, 22%, and 15%, respectively, and decreased glimepiride CL/f by 18%. The recovery of M1 and M2 from urine was not changed.

Warfarin

In an open-label, two-way, crossover study, healthy subjects received 4 mg of glimepiride daily for 10 days. Single 25 mg doses of warfarin were administered 6 days before starting glimepiride and on Day 4 of glimepiride administration. The concomitant administration of glimepiride did not alter the pharmacokinetics of R-and S-warfarin enantiomers. No changes were observed in warfarin plasma protein binding. Glimepiride resulted in a statistically significant decrease in the pharmacodynamic response to warfarin. The reductions in mean area under the prothrombin time (PT) curve and maximum PT values during glimepiride treatment were 3.3% and 9.9%, respectively, and are unlikely to be clinically relevant.