Adult: As conventional tab: Initially, 2.5-5 mg daily, adjusted in increments of 2.5 mg at weekly intervals, based on patient’s response. Max: 20 mg daily. Doses >10 mg may be given in 2 divided doses. As modified-release tab: Initially, 1.5-3 mg daily, may be increased in increments of 1.5 mg at weekly intervals according to patient response. Max: 12 mg daily. Doses >6 mg daily may be given in 2 divided doses. All doses should be given with or immediately after breakfast or with the 1st main meal. Elderly: >70 years Contraindicated.
Special Patient Group
Debilitated and malnourished patients: As conventional tab: Initially, 2.5 mg daily. As modified-release tab: Initially, 0.75 mg daily.
G6PD is an enzyme that mediates the production of NADPH (nicotinamide adenine dinucleotide phosphate hydrogen) and ribose-5-phosphate. Individuals with polymorphic G6PD variants and haplotypes have been associated with variable drug response, and those with G6PD deficiency may experience an increased risk of adverse effects.
Based on studies, glibenclamide may induce acute haemolysis in diabetic patients who are carriers of the A-Haplotype 202A/376G (rs1050828 and rs1050829) variants, and the Mediterranean 563T (rs5030868) variant. The A-Haplotype variant has 10-60% deficiency in G6PD enzyme activity while the Mediterranean variant has <10% severely deficient activity.
EMA- and FDA-approved drug labels for glibenclamide cited that glibenclamide administration should be used in caution in patients carrying a G6PD enzyme deficiency due to the risk of acute haemolytic anaemia. The use of non-sulfonylurea alternative treatment is strongly recommended.
Pharmacogenetic testing in G6PD deficient individuals prior to glibenclamide administration has not yet been addressed by currently available references.
Should be taken with food. Take w/ breakfast or the 1st main meal of the day.
History of allergic reactions to sulfonylureas or sulfonamides. Type 1 diabetes mellitus, diabetic ketoacidosis with or without coma, diabetic coma and pre-coma, acute porphyria; severe infection, stress-related states (e.g. trauma, surgical procedures). Severe renal and hepatic impairment. Elderly (>70 years). Pregnancy. Concomitant use with bosentan.
Patient with G6PD deficiency, adrenal or pituitary insufficiency; conditions that increase the risk of developing hypoglycaemia (e.g. during excessive exercise, irregular/missed mealtimes, and insufficient calorie or glucose intake); atherosclerotic CV disease. Patient who have undergone gastric bypass, sleeve gastrectomy. Mild to moderate renal and hepatic impairment. Debilitated and malnourished patients. Lactation.
Significant: Hypoglycaemia, haemolytic anaemia (in G6PD-deficient patients), weight gain. Blood and lymphatic system disorders: Agranulocytosis, leucopenia, thrombocytopenia, neutropenia. Eye disorders: Accommodation changes, blurred vision. Gastrointestinal disorders: Nausea, heartburn, diarrhoea, vomiting, dyspepsia, metallic taste. General disorders and administration site conditions: Fever. Hepatobiliary disorders: Cholestatic jaundice, hepatitis. Immune system disorders: Stevens-Johnson syndrome, urticaria. Investigations: Transitory increased transaminases. Metabolism and nutrition disorders: Syndrome of inappropriate antidiuretic hormone secretion (SIADH), increased appetite. Rarely, disulfiram-like reactions. Skin and subcutaneous tissue disorders: Rash, pruritus, erythema, photosensitivity, porphyria cutanea tarda. Potentially Fatal: Increased CV mortality.
PO: C (manufacturer specific), B (manufacturer specific)
Patient Counseling Information
This drug may cause hypoglycaemia and reduced alertness, if affected, do not drive or operate machinery.
Monitor urine glucose test, fasting blood glucose, HbA1c (at least twice yearly in patients with stable glycaemic control, and quarterly in patients who do not meet treatment goals or with treatment change); signs and symptoms of hypoglycaemia during treatment.
Symptoms: Hypoglycaemia. Management: Symptomatic and supportive treatment. Administer activated charcoal. For mild hypoglycaemia without loss of consciousness or neurological findings, may give oral glucose, or adjust dosage and meal patterns. For hypoglycaemic coma, administer 50% glucose solution via rapid IV inj, followed by continuous infusion of 10% glucose solution to maintain blood glucose levels above 100 mg/dL.
Enhanced hypoglycaemic effect with azapropazone, phenylbutazone, chloramphenicol, ciprofloxacin, co-trimoxazole, sulfonamides, tetracyclines, anticoagulants, disopyramide, TCAs, MAOIs, allopurinol, sulphinpyrazone, probenecid, ACE inhibitors, testosterone, anabolic steroids. Enhanced hypoglycaemic effect and mask the symptoms of hypoglycaemia with β-blockers. Reduced hypoglycaemic effect with rifampicin, barbiturates, diazoxide, chlorpromazine, loop and thiazide diuretics, oestrogens, progesterone, oral contraceptives, corticosteroids, thyroid hormones. Increased plasma concentrations with miconazole, fluconazole. Additive effect with clofibrate. May increase plasma levels of ciclosporin. May alter anticoagulant effects of warfarin. Reduced plasma concentration and exposure with colesevelam. Potentially Fatal: Increased risk of hepatotoxicity with bosentan.
Alcohol may enhance hypoglycaemic effect or cause rare disulfiram-like reactions.
Description: Glibenclamide lowers blood glucose concentration by stimulating the secretion of insulin from the pancreatic β-cells. It also reduces glucose output from and the liver and increases insulin sensitivity at peripheral target sites. Synonym: Glyburide Onset: Increase in serum insulin levels: 15-60 minutes. Duration: ≤24 hours. Pharmacokinetics: Absorption: Readily absorbed from the gastrointestinal tract. Time to peak plasma concentration: 2-4 hours. Distribution: Crosses placenta. Plasma protein binding: 99% (extensive), mainly to albumin. Metabolism: Almost completely metabolised in the liver into weakly active metabolites. Excretion: Via urine (50%) and faeces (50%), as metabolites. Elimination half-life: 10 hours (conventional tab); approx 4 hours (modified-release tab).
Store between 20-25°C. Protect from light and moisture.
A10BB01 - glibenclamide ; Belongs to the class of sulfonylureas. Used in the treatment of diabetes.
Annotation of EMA Label for Glibenclamide and G6PD. Pharmacogenomics Knowledgebase (PharmGKB). https://www.pharmgkb.org/. Accessed 06/11/2019.Annotation of FDA Label for Glibenclamide and G6PD. Pharmacogenomics Knowledgebase (PharmGKB). https://www.pharmgkb.org/. Accessed 06/11/2019.Anon. G6PD - Glyburide (Pharmacogenomics). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 05/11/2019.Anon. Glyburide. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 05/11/2019.Buckingham R (ed). Glibenclamide. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 05/11/2019.Glynase PresTab Tablets (Pharmacia and Upjohn Company LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 05/11/2019.Joint Formulary Committee. Glibenclamide. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 05/11/2019.Very Important Pharmacogene: G6PD. Pharmacogenomics Knowledgebase (PharmGKB). https://www.pharmgkb.org/. Accessed 06/11/2019.