Tolbutamide

(BAN, rINN)
Tolbutamide Chemical formula
Synonyms: Butamidum; Tolbutamid; Tolbutamida; Tolbutamidas; Tolbutamidi; Tolbutamidum; Tolglybutamide. 1-Butyl-3-tosylurea; 1Butyl-3p-tolylsulphonylurea.
Cyrillic synonym: Тольбутамид.

💊 Chemical information

Chemical formula: C12H18N2O3S = 270.3.
CAS — 64-77-7 (tolbutamide); 473-41-6 (tolbutamide sodium).
ATC — A10BB03; V04CA01.
ATC Vet — QA10BB03; QV04CA01.

Pharmacopoeias.

In Chin., Eur., Int., Jpn, and US.

Ph. Eur. 6.2

(Tolbutamide). A white or almost white, crystalline powder. Practically insoluble in water; soluble in alcohol and in acetone. It dissolves in dilute solutions of alkali hydroxides.

USP 31

(Tolbutamide). A white or practically white, practically odourless, crystalline powder. Practically insoluble in water; soluble in alcohol and in chloroform.

💊 Adverse Effects, Treatment, and Precautions

Tolbutamide was implicated in the controversial reports of excess cardiovascular mortality associated with oral hypoglycaemic therapy. Thrombophlebitis with thrombosis has occurred after the intravenous injection of tolbutamide sodium, but this is usually painless and the vein gradually recovers. Rapid injection may cause a transient mild pain or sensation of heat in the vein. The BNF has suggested that tolbutamide may be suitable for use in patients with renal impairment, but that careful monitoring of blood-glucose concentration is essential. UK licensed product information recommends that it should not be used in patients with severe renal impairment.

Breast feeding.

Tolbutamide is distributed into breast milk in relatively low quantities.1 The American Academy of Pediatrics2states that, although usually compatible with breast feeding, use of tolbutamide by breast-feeding mothers may possibly result in jaundice in the infant.
1. Moiel RH, Ryan JR. Tolbutamide orinase in human breast milk. Clin Pediatr (Phila) 1967; 6: 480
2. American Academy of Pediatrics. The transfer of drugs and other chemicals into human milk. Pediatrics 2001; 108: 776–89. Correction. ibid.; 1029. Also available at: http://aappolicy.aappublications.org/cgi/content/full/ pediatrics%3b108/3/776 (accessed 08/07/04)

Porphyria.

Tolbutamide has been associated with acute attacks of porphyria and is considered unsafe in porphyric patients.

💊 Pharmacokinetics

Tolbutamide is readily absorbed from the gastrointestinal tract and is extensively bound to plasma proteins; the half-life is generally within the range of 4 to 7 hours but may be considerably longer. Tolbutamide is metabolised in the liver by hydroxylation mediated by the cytochrome P450 isoenzyme CYP2C9. It is excreted in the urine chiefly as metabolites with little hypoglycaemic activity. Tolbutamide has been detected in breast milk.

💊 Uses and Administration

Tolbutamide is a sulfonylurea antidiabetic. It is given orally in the treatment of type 2 diabetes mellitus and has a duration of action of about 10 hours. The usual initial dose in type 2 diabetes mellitus may range from 1 to 2 g daily, given either as a single dose with breakfast or, more usually, in divided doses. Maintenance doses usually range from 0.25 to 2 g daily. Although it is unlikely that the response will be improved by increasing the dose further, daily doses of 3 g have been given. Tolbutamide sodium (C 12 H 17 N 2 NaO 3 S = 292.3) has sometimes been used in the diagnosis of insulinoma as well as other pancreatic disorders including diabetes mellitus. The equivalent of 1 g of tolbutamide is given by intravenous injection as a 5% solution usually over 2 to 3 minutes. Tolbutamide sodium 1.08 g is equivalent to about 1 g of tolbutamide.

Diagnosis and testing.

References.
1. McMahon MM, et al. Diagnostic interpretation of the intravenous tolbutamide test for insulinoma. Mayo Clin Proc 1989; 64: 1481–8
2. Marks V. Diagnosis and differential diagnosis of hypoglycemia. Mayo Clin Proc 1989; 64: 1558–61.

💊 Preparations

BP 2008: Tolbutamide Tablets; USP 31: Tolbutamide for Injection; Tolbutamide Tablets.

Proprietary Preparations

Austral.: Rastinon; Cz.: Dirastan; Denm.: Arcosal; Ger.: Orabet; Hong Kong: Diatol; Israel: Orsinon; Mex.: Artosin; Bioglusil†; Dabetil; Diatelan; Diaval; Flusan; Ifumelus†; Rastinon; NZ: Diatol; Pol.: Diabetol; S.Afr.: Tyd adex; Singapore: Tolmide; USA: Orinase; Orinase Diagnostic.
Published December 02, 2018.