Diabetol (Tolbutamide)

Diabetol is a brand name for tolbutamide, a first-generation sulfonylurea oral hypoglycemic medication for T2D.

Mechanism of Action

Tolbutamide blocks ATP-sensitive potassium channels (K_ATP) on pancreatic beta-cell plasma membranes. This blockade causes depolarization, opening voltage-gated calcium channels. The resulting calcium influx triggers insulin granule exocytosis, increasing circulating insulin levels and lowering blood glucose.

Clinical Use

  • Indication: Adjunct to diet and exercise in adults with type 2 diabetes when glycemic control is insufficient by lifestyle alone.
  • Not for: Type 1 diabetes, diabetic ketoacidosis.
  • Route: Oral (tablets).
  • Standard dosing: 500–2000 mg/day (typical tablets are 500 mg); maximum 3000 mg/day.
  • Duration: Short-acting (half-life 4.5–6.5 hours), preferred in elderly due to rapid clearance.

Properties

PropertyDetail
ClassFirst-generation sulfonylurea
Brand namesDiabetol, Orinase, Tol-Tab
ATC codeA10BB03
MetabolismHepatic (CYP2C19-mediated)
ExcretionRenal
Protein binding96%

Side Effects

  • Hypoglycemia
  • Weight gain
  • Hypersensitivity (cross-allergenicity with sulfonamides)
  • Drug interactions: enhanced hypoglycemia with salicylates, cimetidine, insulin

Note on 60mg Dose

The standard available formulation is 500 mg tablets. The “60 mg” noted in some patient medication lists does not match any standard tolbutamide dosage form. Possible explanations include: misrecorded dosage, a different drug sharing the name, or a reference to 60 tablets rather than milligrams. This discrepancy should be verified against original pharmacy records.

Status

Tolbutamide (Orinase) was discontinued by the manufacturer in 2000. It has been largely replaced by newer, second-generation sulfonylureas (glibenclamide/glyburide, gliclazide, glimepiride) with improved safety profiles. It is now rarely used in contemporary clinical practice.

References