Select therapeutic use:
Indications for XENAZINE:
Individualize. Initially 12.5mg once daily in the AM, then 12.5mg twice daily after one week. Titrate slowly at weekly intervals by 12.5mg. Doses of 37.5–50mg/day should be given in a 3 times/day regimen, max 25mg/dose. Patients who require ≥50mg/day should be genotyped for CYP2D6. Poor metabolizers (CYP2D6): max 25mg/dose and 50mg/day; extensive and intermediate metabolizers: max 37.5mg/dose and 100mg/day. Concomitant strong CYP2D6 inhibitors (eg, paroxetine, fluoxetine, quinidine): reduce tetrabenazine dose by ½; moderate to weak CYP2D6 inhibitors: not evaluated. Retitrate if therapy interrupted for more than 5 days.
Depression. Suicidal ideation. Hepatic impairment. Concomitant MAOIs. During or within 20 days of stopping reserpine.
Avoid in congenital long QT syndrome or history of cardiac arrhythmias. Bradycardia. Hypokalemia. Hypomagnesemia. Recent MI. Unstable heart disease. Cardiovascular disease. History of depression, suicidal ideation, or breast cancer. Monitor for depression, emotional lability, akathisia. Poor CYP2D6 metabolizers. Reevaluate periodically. Pregnancy (Cat.C). Nursing mothers: not recommended.
See Contraindications. Avoid concomitant other drugs that can cause QT prolongation (eg, chlorpromazine, thioridazine, ziprasidone, moxifloxacin, quinidine, procainamide, amiodarone, sotalol). Potentiated by CYP2D6 inhibitors (eg, paroxetine, fluoxetine). Increased risk of neuroleptic malignant syndrome, extrapyramidal syndrome with neuroleptics, dopamine antagonists. Additive CNS depression with alcohol, other CNS depressants.
Vesicular monoamine transporter 2 (VMAT2) inhibitor.
Sedation, fatigue, insomnia, depression, dysphagia, akathisia, nausea, parkinsonism, QTc prolongation, orthostatic hypotension, elevated serum prolactin; rarely: neuroleptic malignant syndrome, tardive dyskinesia, extrapyramidal effects.