Increased chloramphenicol conc. Increased effects of oral anticoagulants eg, warfarin. Increased paracetamol absorption by drugs increasing gastric emptying eg, metoclopramide. Decreased paracetamol absorption by drugs decreasing gastric emptying eg, propantheline or narcotic analgesics, pethidine. Increased paracetamol toxicity by enzyme-inducing agents eg, alcohol or phenytoin. Increased pseudoephedrine absorption by Al hydroxide mixt eg, antacids. Decreased pseudoephedrine absorption by kaolin. Reduced hypotensive effects of certain neurone blockers eg, bretylium. Potentiated chlorpheniramine sedative effects w/ alcohol, barbiturates, anxiolytics, TCAs, hypnotics or other CNS depressants. Increased chlorpheniramine antimuscarinic effects by other antimuscarinic drugs.