Ketoconazole increases the blood glucose lowering effects of
tolbutamide in healthy subjects and possibly increases the effects of rosiglitazone and pioglitazone.
If
ketoconazole is added to
tolbutamide, patients should be warned to be alert for any evidence of increased hypoglycaemia; adjust the
tolbutamide dose as necessary. It may be prudent to increase the frequency of blood glucose monitoring if
ketoconazole is given with rosiglitazone or pioglitazone.