<prompt> Drugs causing constipation are All exceptVerapamilQuinidineMAO inhibitorTricyclic antidepressants  <response>: Refer kDT 6e p530,655 drugs causing constipation are Verapamil MAO inhibitor Tricyclic antidepressants Ferrous sulfate other impoant drugs which cause constipation are Ganglion blockers Opioid Calcium carbonate Sedatives Anti histamine Laxative abuse itself Quinidine causes diarrhoea 