<p>Increased CNS depression with CNS depressants such as opiates or other analgesics, barbiturates or other sedatives, general anaesthetics, or alcohol. Increased risk of side effects with drugs with antimuscarinic properties e.g. TCA, antiparkinsonian drugs. Antagonised effects of dopaminergic drugs such as levodopa. Increased risk of hypotension with antihypertensives, trazodone. Reverses antihypertensive effect of guanethidine. Increased risk of severe extrapyramidal side-effects or severe neurotoxicity with lithium. Possible decrease in absorption with antacids.</p>