Tolazamide toxicity

Tolazamide, tolbutamide, chlorpropamide Older sulfonylureas, lower potency, greater toxicity rarely used ... 

Note Tolazamide is a sulfonamide and can be absorbed systemically. Sulfonamides can produce severe, possibly fatal, reactions such as toxic epidermal necrolysis and Stevens-Johnson syndrome... 

Large and toxic doses of phenytoin have been observed to cause hyperglycaemia, but normal therapeutic doses do not usually affect the control of diabetes. Two isolated cases of phenytoin toxicity have been attributed to the use of tolazamide or tolbutamide. Miglitol does not affect the bioavailability of phenytoin. 

Tolbutamide 500 mg two or three times daily was given to 17 patients taking phenytoin 100 to 400 mg daily. The patients had a transient 45% rise in the amount of non-protein-bound phenytoin by day 2, which had disappeared by day 4. The introduction to this report briefly mentions a man given phenytoin and tolazamide who developed phenytoin toxicity, which disappeared when the tolazamide was replaced by insulin. A woman previously uneventfully treated with phenytoin and tolbutamide developed toxicity on a later occasion when she took tolbutamide with twice the previous dose of phenytoin. One study in healthy subjects found that miglitol 100 mg three times daily for 5 days did not affect the bioavailability of a single 400-mg dose of phenytoin. ... 

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