Inhibition of absorption & efficacy w/ cholestyramine, colestipol or antacids containing Al hydroxide &/or smectite (Al oxide). Affect the absorption of ciclosporin. Reduce the absorption of ciprofloxacin. Decreased C
max & AUC of nitrendipine. Decreased therapeutic effect of dapsone. May increase hepatic cholesterol secretion & biliary lithiasis w/ oestrogenic hormones & blood cholesterol-lowering agents eg, clofibrate.