Differentiating the Clinical Presentations of Tardive Dyskinesia (TD) and Drug-Induced Parkinsonism

See Important Safety Information below; Prescribing Information including Boxed Warning: bit.ly/3uNLgIg. AUSTEDO XR/AUSTEDO can cause depression, suicidal thoughts, or actions in patients with HD. Don’t use if you have liver problems; are taking reserpine, tetrabenazine, or valbenazine.
INDICATIONS & USAGE
AUSTEDO XR is indicated in adults for the treatment of chorea associated with Huntington's disease (HD) & for the treatment of tardive dyskinesia (TD).
IMPORTANT SAFETY INFORMATION Depression & Suicidality in HD Patients: AUSTEDO XR can increase the risk of depression & suicidal thoughts & behavior (suicidality) in HD Patients. Balance the risks of depression & suicidality with the clinical need for treatment of chorea. Closely monitor patients for the emergence or worsening of depression, suicidality, or unusual changes in behavior. Inform patients, their caregivers, & families of the risk of depression & suicidality & instruct them to report behaviors of concern promptly to the treating physician. Exercise caution when treating patients with a history of depression or prior suicide attempts or ideation. AUSTEDO XR is contraindicated in patients who are suicidal, & in patients with untreated or inadequately treated depression.
Contraindications: AUSTEDO XR is contraindicated in HD patients who are suicidal, or have untreated or inadequately treated depression. AUSTEDO XR is also contraindicated in: patients with hepatic impairment; patients taking reserpine or within 20 days of discontinuing reserpine; patients taking monoamine oxidase inhibitors (MAOIs), or within 14 days of discontinuing MAOI therapy; & patients taking tetrabenazine or valbenazine.
Clinical Worsening & Adverse Events in HD Patients: AUSTEDO XR may cause a worsening in mood, cognition, rigidity, & functional capacity. Prescribers should periodically re-evaluate the need for AUSTEDO XR in their patients by assessing the effect on chorea & possible adverse effects.
QTc Prolongation: AUSTEDO XR may prolong the QT interval, but the degree of QT prolongation is not clinically significant when AUSTEDO XR is administered within the recommended dosage range. AUSTEDO XR should be avoided in patients with congenital long QT syndrome & in patients with a history of cardiac arrhythmias.
Neuroleptic Malignant Syndrome (NMS), a potentially fatal symptom complex reported in association with drugs that reduce dopaminergic transmission, has been observed in patients receiving tetrabenazine. The risk may be increased by concomitant use of dopamine antagonists or antipsychotics. The management of NMS should include immediate discontinuation of AUSTEDO XR; intensive symptomatic treatment & medical monitoring; & treatment of any concomitant serious medical problems.
Akathisia, Agitation, & Restlessness: AUSTEDO XR may increase the risk of akathisia, agitation, & restlessness. The risk of akathisia may be increased by concomitant use of dopamine antagonists or antipsychotics. If a patient develops akathisia, the AUSTEDO XR dose should be reduced; some patients may require discontinuation of therapy.
Parkinsonism: AUSTEDO XR may cause parkinsonism in TD or HD patients. The risk of parkinsonism may be increased by concomitant use of dopamine antagonists or antipsychotics. If a patient develops parkinsonism, the AUSTEDO XR dose should be reduced; some patients may require discontinuation of therapy.
Sedation & Somnolence: Sedation is a common dose-limiting adverse reaction of AUSTEDO XR. Patients should not perform activities requiring mental alertness, such as operating a motor vehicle or hazardous machinery, until they are on a maintenance dose of AUSTEDO XR & know how the drug affects them. Concomitant use of alcohol or other sedating drugs may have additive effects & worsen sedation & somnolence.
Hyperprolactinemia: Tetrabenazine elevates serum prolactin concentrations in humans. If there is a clinical suspicion of symptomatic hyperprolactinemia, appropriate laboratory testing should be done & consideration should be given to discontinuation of AUSTEDO XR.
Binding to Melanin-Containing Tissues: Deutetrabenazine or its metabolites bind to melanin-containing tissues & could accumulate in these tissues over time. Prescribers should be aware of the possibility of long-term ophthalmologic effects.
Common Adverse Reactions: The most common adverse reactions for AUSTEDO (greater than 8% & greater than placebo) in a controlled clinical study in HD patients were somnolence, diarrhea, dry mouth, & fatigue. The most common adverse reactions for AUSTEDO (4% & greater than placebo) in controlled clinical studies in TD patients were nasopharyngitis & insomnia. Adverse reactions with AUSTEDO XR are expected to be similar to AUSTEDO.