Drug information of Tolbutamide
Tolbutamide is an oral antihyperglycemic agent used for the treatment of non-insulin-dependent diabetes mellitus (NIDDM).
Mechanism of effect
Sulfonylureas lower blood glucose in patients with NIDDM by directly stimulating the acute release of insulin from functioning beta cells of pancreatic islet tissue by an unknown process that involves a sulfonylurea receptor (receptor 1) on the beta cell.
Sulfonylureas inhibit the ATP-potassium channels on the beta cell membrane and potassium efflux, which results in depolarization and calcium influx, calcium-calmodulin binding, kinase activation, and release of insulin-containing granules by exocytosis, an effect similar to that of glucose.
Tolbutamide lowers blood sugar by stimulating the pancreas to secrete insulin and helping the body use insulin efficiently. The pancreas must be able to produce insulin for this drug to work.
Half-Life: 4.5-6.5 hr
Duration: 6-24 hr
Max Effect: 5-8 hr
Time to peak, serum: 3-4 hr
Protein Bound: 80-99%
Vd: 0.15 L/kg
Metabolism: extensively, in liver to inactive metabolites by hepatic P450 enzyme CYP2C9
Metabolites: carboxytolbutamide, hydroxymethyltolbutamide (inactive)
Excretion: mainly in urine 70-80%
- Hemodialysis: No
- Peritoneal dialysis: No data
Drug indicationsdiabetes mellitus
Type 2 Diabetes
250 mg-2 g PO qDay or q8-12hr; not to exceed 3 g/day; maintenance dose >2 g/day seldom required
Divided doses may minimize gastrointestinal side effects
Safety and efficacy not established
Drug contraindicationsHypersensitivity , Diabetes ketoacidosis
Hypersensitivity, sulfa allergy Type I diabetes, diabetic ketoacidosis
Side effectsnausea , vomiting , Cutaneous Reaction , aplastic anemia, , Agranulocytosis , thrombocytopenia , Dysulfamine-like reactions
InteractionsChloramphenicol , Clofibrate , Thyrotropin alfa , Gatifloxacin , aminolevulinic acid oral , Phenindione , Peginterferon alfa-2b , Canagliflozin , lumacaftor and Ivacaftor , Grepafloxacin , Aminolevulinic acid topical , Cannabidiol , Alclometasone , flurandrenolide
Patients with hypoglycemia, when caloric intake is decreased or there is increased stress due to infection, fever, trauma, or surgery (may need to discontinue treatment)
Risk of cardiovascular mortality increases with oral hypoglycemic drug treatments compared to treatment with diet alone or diet plus insulin
Risk of sulfonylurea-induced hemolytic anemia may increase in patients iwth glucose-6-phosphate dehydrogenase deficiency
Points of recommendation
- Be careful if you have G6PD deficiency. Anemia may happen.
- Do not drive if your blood sugar has been low. There is a greater chance of you having a crash.
- Check your blood sugar as you have been told by your doctor.
- Have blood work checked as you have been told by the doctor. Talk with the doctor.
- This medicine may affect certain lab tests. Tell all of your health care providers and lab workers that you take tolbutamide.
- Talk with your doctor before you drink alcohol.
- It may be harder to control your blood sugar during times of stress like when you have a fever, an infection, an injury, or surgery. A change in level of physical activity or exercise and a change in diet may also affect your blood sugar. Talk with your doctor.
- Follow the diet and workout plan that your doctor told you about.
- Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using tolbutamide while you are pregnant.
- To gain the most benefit, do not miss doses.
- Keep taking tolbutamide as you have been told by your doctor or other health care provider, even if you feel well.
- Take a missed dose as soon as you think about it.
- If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
- Do not take 2 doses at the same time or extra doses.
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