Decrease dosage of paracetamol if taken for a prolonged period of time w/ anticoagulant drugs eg, warfarin. Increased absorption w/ substances that increase gastric emptying eg, metoclopramide. Decreased absorption w/ substances that decrease gastric emptying eg, propantheline, antidepressants w/ anticholinergic properties & narcotic analgesics. May increase chloramphenicol conc. Risk of paracetamol toxicity may be increased in patients receiving other potentially hepatotoxic drugs or drugs that induce liver microsomal enzymes eg, alcohol & anticonvulsant agents. Paracetamol excretion may be affected & plasma conc altered when given w/ probenecid. Colestyramine reduces the absorption of paracetamol if given w/in 1 hr of paracetamol.