Diclofenac Colestipol

Simultaneous colestipol modestly reduced the oral absorption of diclofenac, but had no effect on ibuprofen absorption. 

A single-dose, crossover study in 6 healthy, fasting subjects found that the simultaneous use of colestyramine 8 g markedly reduced the AUC of a single 100-mg oral dose of enteric-coated diclofenac by 62% and reduced its maximum plasma levels by 75%. Colestipol 10 g reduced the diclofenac AUC by 33% and its maximum plasma levels by 58%. ... 

The studies of simultaneous oral use suggest that the anion exchange resin colestyramine, and to a lesser extent colestipol, bind anionic NSAIDs (e.g. diclofenac) in the gut, so reducing their absorption. The studies showing reduced plasma levels when colestyramine was given after intravenous oxicams or separated by at least 3 hours from some oral NSAIDs, suggest that colestyramine can reduce the enterohepatic recirculahon of these drugs. 

The reduction in diclofenac absorption with colestipol may be clinically relevant if the combination is required monitor well. Note that it is usually recommended that other drugs are given 1 hour before or 4 hours after colestipol. 

Al-Balla SR, El-Sayed YM, Al-Meshal Gouda MW. The effects of cholestyramine and colestipol on tile absorption of diclofenac in man. IntJ Clin Pharmacol Ther( 994)32,441 5. 

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