Tolbutamide


Concise Prescribing Info
Indications/Uses
Type 2 DM.
Dosage/Direction for Use
Adult : PO Initial: 1-2 g/day as a single dose in the morning or in divided doses. Maintenance: 0.25-2 g/day. Max: 3 g/day.
Dosage Details
Oral
Type 2 diabetes mellitus
Adult: Initially, 1-2 g daily as a single dose in the morning or in divided doses. Maintenance: 0.25-2 g daily. Max: 3 g daily.
Elderly: Initial: 250 mg 1-3 times/day. Usual: 0.5-2 g. Max: 3 g/day.
Renal Impairment
Dose adjustment may be needed. Severe: Contraindicated.
Hepatic Impairment
Dose adjustment may be needed.
Administration
Should be taken with food.
Contraindications
Hypersensitivity to tolbutamide, sulfonylureas. Type 1 DM, diabetes w/ ketosis, acidosis, diabetic coma, or other acute complications (e.g. major surgery, severe infection or trauma), porphyria. Severe renal impairment.
Special Precautions
Patient w/ G6PD deficiency, adrenocortical or thyroid function impairment. Hepatic and mild to moderate renal impairment. Elderly, debilitated and malnourished patients. Pregnancy and lactation.
Adverse Reactions
Hypoglycaemia, nausea, epigastric fullness, heartburn, headache, pruritus, erythema, and urticarial, morbilliform or maculopapular eruptions, wt gain, hyponatraemia, syndrome of inappropriate secretion of antidiuretic hormone (SIADH), photosensitivity reactions. Rarely, hepatic dysfunction, jaundice, leucopenia, thrombocytopenia, pancytopenia, agranulocytosis, aplastic anaemia, and haemolytic anaemia.
Patient Counseling Information
Adhere strictly to the prescribed diabetic diet.
MonitoringParameters
Monitor blood glucose, glycosylated Hb level, signs and symptoms of hypoglycaemia.
Overdosage
Symptoms: Hypoglycaemia. Management: In conscious patient, admin glucose or 3-4 lumps of sugar w/ water. In comatose patient, admin up to 50 mL of 50% glucose soln via rapid IV inj followed by continuous infusion of a more dilute (10%) glucose soln.
Drug Interactions
Hypoglycaemic effect enhanced by protein-bound drugs (e.g. oral anticoagulants, hydantoins, salicylates, other NSAIDs, sulfonamides), chloramphenicol, MAOIs. Decreased hypoglycaemic effect w/ thiazides, other diuretics, phenothiazines, thyroid products, oestrogens, OC, phenytoin, nicotinic acid, corticosteroids, sympathomimetics, Ca channel blockers and isoniazid. Concomitant use w/ certain antifungals (e.g. miconazole, fluconazole) may increase plasma concentrations of tolbutamide.
Food Interaction
Disulfiram-like reaction w/ alcohol.
Lab Interference
May give false-positive result for urinary albumin w/ test using heat and acetic acid or sulfosalicylic acid. May interfere w/ test results of radioactive iodine uptake by decreasing uptake of radioactive iodine.
Action
Description: Tolbutamide lowers blood glucose concentration principally by stimulating the secretion of endogenous insulin from pancreatic β-cells. It may enhance peripheral sensitivity to insulin and reduce basal hepatic glucose production during long-term admin.
Onset: 1 hr.
Duration: 6-24 hr.
Pharmacokinetics:
Absorption: Readily absorbed from the GI tract. Time to peak plasma concentration: W/in 3-5 hr.
Distribution: Distributed into breast milk. Volume of distribution: 0.15 L/kg. Plasma protein binding: Approx 95%.
Metabolism: Metabolised in the liver via hydroxylation mediated by CYP2C9 isoenzyme.
Excretion: Via urine (75-85%) mainly as metabolites and faeces. Half-life: 4-7 hr.
Chemical Structure

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Storage
Store between 15-30°C.
MIMS Class
Disclaimer: This information is independently developed by MIMS based on Tolbutamide from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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