Increased CNS depression w/ alcohol, hypnotics, sedatives & strong analgesics. Antagonised action of adrenaline & other sympathomimetic agents. Reversed BP-lowering effects of adrenergic-blocking agents eg, guanethidine & clonidine. Impaired anti-parkinsonian effects of L-dopa, anticonvulsant effects, TCAs metabolism & control of diabetes. Increased effects of anticoagulants. Enhanced anticholinergic effects w/ anti-parkinsonian drugs. Enhanced cardiac-depressant effects of quinidine, absorption of corticosteroid, digoxin & neuromuscular-blocking agents. Severe hypotension w/ ACE inhibitors. Increased plasma conc w/ β-blockers. Inhibited absorption w/ Al- or Mg-containing antacids, adsorbent antidiarrheals. Decreased stimulant effect w/ amphetamines. Intensified anticholinergic side effects of medications w/ anticholinergic action.