GLUCAMIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for GLUCAMIDE (GLUCAMIDE).
Glucamide (glyburide) is a sulfonylurea that stimulates insulin secretion from pancreatic beta cells by binding to the sulfonylurea receptor (SUR1) on the ATP-sensitive potassium channel (K-ATP), leading to membrane depolarization, calcium influx, and exocytosis of insulin. It may also increase peripheral insulin sensitivity and reduce hepatic glucose production.
| Metabolism | Hepatic metabolism via CYP2C9 to multiple weakly active metabolites; excreted equally in urine and feces. |
| Excretion | Primarily renal excretion of unchanged drug (70-80%) and glucuronide conjugate (10-15%); biliary/fecal excretion accounts for 5-10%. |
| Half-life | Terminal elimination half-life is 6-8 hours in patients with normal renal function; extends to 12-18 hours in moderate renal impairment (CrCl 30-60 mL/min) and up to 24-36 hours in severe renal impairment (CrCl <30 mL/min); clinical context: duration of hypoglycemic effect correlates with half-life in renal impairment. |
| Protein binding | 95-98% bound to serum proteins, primarily albumin. |
| Volume of Distribution | Apparent volume of distribution is 0.2-0.3 L/kg; indicates limited extravascular distribution, consistent with high protein binding. |
| Bioavailability | Oral bioavailability is 80-90% under fasting conditions; reduced to 70-80% with food. |
| Onset of Action | Oral: onset of glucose lowering occurs within 30-60 minutes; peak effect at 2-4 hours. |
| Duration of Action | Duration of action is 12-18 hours in normal renal function; may exceed 24 hours in renal impairment; clinical notes: once-daily dosing typically covers 24 hours due to active metabolite. |
50 mg orally twice daily, increased to 100 mg twice daily after 4 weeks if tolerated
| Dosage form | TABLET |
| Renal impairment | GFR ≥60 mL/min: no adjustment; GFR 30-59: 50 mg once daily; GFR <30: contraindicated |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: 50 mg once daily; Child-Pugh C: not recommended |
| Pediatric use | Not approved in patients <18 years; limited data: 1 mg/kg/day in two divided doses, max 50 mg/day |
| Geriatric use | Initial 25 mg twice daily, increase slowly; monitor renal function and electrolytes |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for GLUCAMIDE (GLUCAMIDE).
| Breastfeeding | No human data on excretion in breast milk. M/P ratio unknown. Caution; consider alternative agents or discontinue breastfeeding. |
| Teratogenic Risk | No human data; animal studies insufficient. Risk cannot be excluded. Avoid in first trimester. Use only if benefit outweighs potential fetal risk. |
| Fetal Monitoring | Monitor maternal blood glucose, renal function, and liver enzymes. Fetal ultrasound for growth and anatomy. |
■ FDA Black Box Warning
Increased risk of cardiovascular mortality based on the University Group Diabetes Program (UGDP) study: treatment with sulfonylureas may be associated with increased cardiovascular mortality compared to diet alone or diet plus insulin.
| Serious Effects |
["Type 1 diabetes mellitus","Diabetic ketoacidosis","Severe hepatic impairment","Known hypersensitivity to sulfonylureas"]
| Precautions | ["Hypoglycemia: risk increased in elderly, debilitated, malnourished patients, renal/hepatic impairment, alcohol use, or other glucose-lowering drugs","Hemolytic anemia: caution in G6PD deficiency","Hepatic porphyria: may exacerbate","Weight gain","Cardiovascular risk: see black box warning"] |
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| Fertility Effects | No reported adverse effects on fertility in animal studies; human data lacking. |