Inhibition of absorption & efficacy w/ colestyramine, colestipol or antacids containing Al hydroxide &/or smectite (Al oxide). Increased/decreased absorption of ciclosporin. Reduce C
max & AUC of nitrendipine. Reduction of therapeutic effect of dapsone. May increase biliary lithiasis w/ oestrogenic hormones & blood cholesterol-lowering lowering substances eg, clofibrate.