Insulin Colestipol

A report suggests that the hypocholesterolaemic effect of colestipol is unaffected in insulin-treated diabetics but it may be ineffective in those taking phenformin and sulphonylureas. Diabetic control was not affected. Colestyramine may enhance the effect of acarbose, and insulin levels may rebound if both drugs are stopped at the same time. There is evidence that the absorption of glipizide may be reduced by about 30% if it is taken at the same time as colestyramine, but tolbutamide does not appear to be affected. 

The concurrent use of phenformin and a sulphonylurea (chlorpropamide, tolbutamide or tolazamide) inhibited the normal hypocholesterolaemic effects of the colestipol in 12 diabetics with elevated serum cholesterol levels. No such antagonism was seen in two patients with type 2 diabetes receiving insulin. The control of diabetes was not affected by the colestipol. ... 

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