Product Information

Registration Status: Active

TOLMIDE TABLET 500mg is approved to be sold in Singapore with effective from 1990-04-20. It is marketed by BEACONS PHARMACEUTICALS PTE LTD, with the registration number of SIN04257P.

This product contains Tolbutamide 500mg in the form of TABLET. It is approved for ORAL use.

This product is manufactured by BEACONS PHARMACEUTICALS PTE LTD in SINGAPORE.

It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.



Tolbutamide is an oral antihyperglycemic agent used for the treatment of non-insulin-dependent diabetes mellitus (NIDDM). It is structurally similar to acetohexamide, chlorpropamide and tolazamide and belongs to the sulfonylurea class of insulin secretagogues, which act by stimulating β cells of the pancreas to release insulin. Sulfonylureas increase both basal insulin secretion and meal-stimulated insulin release. Medications in this class differ in their dose, rate of absorption, duration of action, route of elimination and binding site on their target pancreatic β cell receptor. Sulfonylureas also increase peripheral glucose utilization, decrease hepatic gluconeogenesis and may increase the number and sensitivity of insulin receptors. Sulfonylureas are associated with weight gain, though less so than insulin. Due to their mechanism of action, sulfonylureas may cause hypoglycemia and require consistent food intake to decrease this risk. The risk of hypoglycemia is increased in elderly, debilitated and malnourished individuals. Tolbutamide appears to be metabolized in the liver. Tolbutamide and its metabolites are excreted in urine (75-85%) and feces.


For treatment of NIDDM (non-insulin-dependent diabetes mellitus) in conjunction with diet and exercise.

Mechanism of Action

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.


Readily absorbed following oral administration. Tolbutamide is detectable in plasma 30-60 minutes following oral administration of a single dose with peak plasma concentrations occurring within 3-5 hours. Absorption is unaltered if taken with food but is increased with high pH.
Metabolized in the liver principally via oxidation of the p-methyl group producing the carboxyl metabolite, 1-butyl-3-p-carboxyphenylsulfonylurea. May also be metabolized to hydroxytolbutamide. Tolbutamide does not undergo acetylation like antibacterial sulfonamides as it does not have a p-amino group.


Oral, mouse: LD50 = 2600 mg/kg

Active Ingredient/Synonyms

1-Butyl-3-(P-methylphenylsulfonyl)urea | 1-Butyl-3-(P-tolylsulfonyl)urea | 1-Butyl-3-tosylurea | 1-P-Toluenesulfonyl-3-butylurea | 3-(P-Tolyl-4-sulfonyl)-1-butylurea | N-(4-Methylbenzenesulfonyl)-n'-butylurea | N-(4-Methylphenylsulfonyl)-n'-butylurea | N-(P-Methylbenzenesulfonyl)-n'-butylurea | N-(Sulfonyl-P-methylbenzene)-n'-N-butylurea | N-Butyl-n'-(4-methylphenylsulfonyl)urea | N-Butyl-N'-(p-tolylsulfonyl)urea | N-Butyl-n'-P-toluenesulfonylurea | N-N-Butyl-n'-tosylurea | Orinase (tn) | Tolbutamida | Tolbutamide | Tolbutamidum | Tolylsulfonylbutylurea | Tolbutamide |

Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.


  1. Health Science Authority of Singapore - Reclassified POM
  2. Drugbank