Antagonized effect of l-dopa & other dopamine agonists. Emergence of extrapyramidal symptoms w/ psychostimulants eg, methylphenidate. Hypotension w/ antihypertensives. Increased plasma conc w/ strong CYP2D6, CYP3A4 &/or P-gp inhibitors eg, itraconazole, ketoconazole, phenothiazines, β-blockers, Ca-channel blockers eg, verapamil, fluoxetine, paroxetine, TCAs, sertraline. Decreased plasma conc w/ strong CYP3A4 &/or P-gp inducers eg, rifampicin, carbamazepine. Potentially raised conc w/ ritonavir & ritonavir-boosted PIs. Increased mortality in elderly w/ furosemide. Increased bioavailability by H2
-receptor antagonists eg, cimetidine, ranitidine. Centrally-acting drugs, alcohol; drugs prolonging QT interval.