Potential risk of ventricular arrhythmia w/ α- & β-sympathomimetic agents (eg, isoprenaline, adrenaline & noradrenaline). Risk of crisis during an operation w/ non-selective MAOIs. May lead to marked hypotension or risk of additive -ve inotropic effect w/ Ca antagonist. Rare increases in serum K levels w/ succinylcholine. Decreased MAC w/ benzodiazepines, nitrous oxide & opiates. Increased metabolism w/ CYP2E1 inducers (eg, INH & alcohol). Increased intensity & duration of neuromuscular blockade w/ nondepolarizing muscle relaxants eg, pancuronium, vecuronium or atracurium.