Verapamil may markedly increase
colchicine levels, which led to neuromyopathy in one man.
Although this is an isolated case, it is in line with the way both drugs interact with other substances. Therefore it would seem prudent to suspect an interaction in the case of otherwise unexplained
colchicine toxicity.
Colestyramine and related drugs
Note that it is usually recommended that other drugs are given one hour before or 4 hours after colestipol and one hour before or 4 to 6 hours after colestyramine. Interactions have therefore only been included where information suggests that different actions may be appropriate.