Risk of serotonin syndrome w/ irreversible, non-selective MAOIs, linezolid & methylene blue. Inhibited metabolism of metoprolol, mequitazine. Reduced efficacy of tamoxifen. Changes in blood levels w/ phenytoin. Prolonged QT interval w/ class IA & III antiarrythmics, antipsychotics, TCAs, sparfloxacin, moxifloxacin, erythromycin IV, pentamidine, halofantrine, astemizole, mizolastine. Risk of increased bleeding w/ oral anticoagulant, aspirin & NSAIDs. Reduced antidepressant activity w/ cyproheptadine. Increased risk of hyponatremia w/ diuretics, desmopressin, carbamazepine, oxcarbazepine. Lowered seizure threshold w/ TCAs, other SSRIs, phenothiazines, butyrophenones, mefloquine, chloroquine, bupropion, tramadol. Drugs metabolized by CYP2D6 eg, fleicainide, propafenone, nebivolol, atomoxetine, carbamazepine. Iproniazid, alcohol, lithium, tramadol, triptans, tryptophan, selegiline, St. John's wort, flecainide, propafenone, nebivolol, atomoxetine, risperidone.