Miscellaneous neurodegenerative disorders:
Indications for: XENAZINE
Huntington's chorea.
Adult Dosage:
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 CYP2D6 metabolizers: max 25mg/dose and 50mg/day; extensive and intermediate metabolizers: max 37.5mg/dose and 100mg/day. Concomitant strong CYP2D6 inhibitors: max 25mg/dose and 50mg/day; moderate to weak CYP2D6 inhibitors: not evaluated. Retitrate if therapy interrupted for more than 5 days.
Children Dosage:
Not established.
XENAZINE Contraindications:
Untreated or inadequately treated depression. Suicidal ideation. Hepatic impairment. During or within 14 days of MAOIs. During or within 20 days of stopping reserpine. Concomitant deutetrabenazine or valbenazine.
Boxed Warning:
Depression and suicidality.
XENAZINE Warnings/Precautions:
Monitor for emergence or worsening of depression, suicidality, or unusual changes in behavior. History of depression or suicidal ideation. Avoid in congenital long QT syndrome, history of cardiac arrhythmias. Bradycardia. Hypokalemia. Hypomagnesemia. History of breast cancer. Discontinue if neuroleptic malignant syndrome (NMS) occurs. Monitor for parkinsonism, akathisia, restlessness, agitation; may need to reduce dose or discontinue treatment. Poor CYP2D6 metabolizers. Reevaluate periodically. Pregnancy. Nursing mothers.
XENAZINE Classification:
Vesicular monoamine transporter 2 (VMAT2) inhibitor.
XENAZINE Interactions:
See Contraindications. Avoid concomitant drugs known to prolong QT interval (eg, chlorpromazine, haloperidol, thioridazine, ziprasidone, moxifloxacin, quinidine, procainamide, amiodarone, sotalol). Potentiated by strong CYP2D6 inhibitors (eg, paroxetine, fluoxetine, quinidine); see Adult. Increased risk of parkinsonism, NMS, akathisia with neuroleptics, dopamine antagonists. Additive CNS depression with alcohol, other CNS depressants.
Adverse Reactions:
Sedation/somnolence, fatigue, insomnia, depression, akathisia, anxiety/anxiety aggravated, nausea, upper respiratory tract infection; parkinsonism, QTc prolongation, orthostatic hypotension, hyperprolactinemia, extrapyramidal effects, dysphagia, potential for long-term ophthalmologic effects.
Generic Drug Availability:
NO
How Supplied:
Tabs—112
