Non-VMAT2 inhibitor treatments for the treatment of tardive dyskinesia

Treatment of tardive dyskinesia with clonazepam: A case report

Clonazepam has some evidence in the treatment of tardive dyskinesia. It can be used as an alternative treatment option in situations where vesicular monoamine transporter 2 inhibitors are not available or when it is not feasible to use them.

Pathophysiology, prognosis and treatment of tardive dyskinesia

Tardive dyskinesia (TD), a movement disorder associated with antipsychotics, most frequently affects the lower face and jaw muscles, but can also affect walking, breathing and use of the hands and limbs. Knowledge of TD among physicians may be limited, and the pathophysiology of TD is poorly understood. We conducted this review to summarise the current knowledge surrounding the pathophysiology of TD and present recommendations for prevention and treatment based on a literature search and roundtable discussion attended by psychiatrists in Japan. It has been suggested that dopamine hypersensitivity, damaged gamma-aminobutyric acidergic neurons and/or increased production of reactive oxygen species may contribute to development of TD. Symptoms can profoundly affect everyday life; patients who develop TD have poorer prognoses, worse health-related quality of life, greater social withdrawal and higher mortality than patients without TD. Traditional treatment options include dietary supplements, although evidence for their effectiveness is low. Among pharmaceutical interventions, there is moderate evidence that switching to the second-generation antipsychotic clozapine, which has a lower affinity for dopamine D₂ receptors than other antipsychotics, may improve symptoms. Vesicular monoamine transporter 2 (VMAT-2) inhibitors, which oppose the increased dopaminergic activity associated with prolonged antipsychotic use by interfering with dopamine uptake and storage, have the strongest evidence for efficacy. VMAT-2 inhibitors are approved in the United States for the treatment of TD, and the first VMAT-2 inhibitor was approved in Japan for this indication in March 2022. Most guidelines recommend treating TD by first reducing the dose of antipsychotics or switching to clozapine or other second-generation antipsychotics, which have a lower association with TD than first-generation antipsychotics. We recommend focusing on prevention and monitoring for TD when prescribing antipsychotics, given that TD is often irreversible. Physicians should treat with antipsychotics only when necessary and at the lowest effective dose, and frequently monitor for TD symptoms.

PLAIN LANGUAGE SUMMARY

Plain Language Summary (In Japanese).

VISUAL SUMMARY

Visual Summary (In Japanese).

Recent Advances in the Pharmacology of Tardive Dyskinesia

Tardive dyskinesia (TD) is a syndrome of abnormal involuntary movements that follows treatment with dopamine D2-receptor antagonists. Recent approval of vesicular monoamine transporter-2 (VMAT2) inhibitors offers hope for reducing the impact of TD. Although these drugs represent a significant advance in patient care and a practical step forward in providing relief for patients with TD, understanding of the pharmacology of TD that could inform future research to prevent and reverse TD remains incomplete. This review surveys evidence for the effectiveness of VMAT2 inhibitors and other agents in the context of theories of pathogenesis of TD. In patients for whom VMAT2 inhibitors are ineffective or intolerable, as well as for extending therapeutic options and insights regarding underlying mechanisms, a review of clinical trial results examined as experimental tests of etiologic hypotheses is worthwhile. There are still compelling reasons for further investigations of the pharmacology of TD, which could generate alternative preventive and potentially curative treatments. Finally, benefits from novel drugs are best realized within an overall treatment strategy addressing the condition and needs of individual patients.

Recent developments in drug-induced movement disorders: a mixed picture

A large and ever-growing number of medications can induce various movement disorders. Drug-induced movement disorders are disabling but are often under-recognised and inappropriately managed. In particular, second generation antipsychotics, like first generation agents, are associated with potentially debilitating side-effects, most notably tardive syndromes and parkinsonism, as well as potentially fatal acute syndromes. Appropriate, evidence-based management is essential as these drugs are being prescribed to a growing population vulnerable to these side-effects, including children and elderly people. Prevention of the development of drug-induced movement disorders is an important consideration when prescribing medications that can induce movement disorders. Recent developments in diagnosis, such as the use of dopamine transporter imaging for drug-induced parkinsonism, and treatment, with the approval of valbenazine and deutetrabenazine, the first drugs indicated for tardive syndromes, have improved outcomes for many patients with drug-induced movement disorders. Future research should focus on development of safer antipsychotics and specific therapies for the different tardive syndromes and the treatment of drug-induced parkinsonism.

Valbenazine in the treatment of tardive dyskinesia

Tardive dyskinesia (TD) is a bothersome and – at times, disabling – movement disorder associated with exposure to dopamine receptor antagonist medications. On 11 April 2017, valbenazine became the first US FDA-approved medication indicated for the treatment of TD. Valbenazine is a vesicular monoamine transporter 2 (VMAT2) inhibitor that decreases the abnormal movements of TD. The FDA considered valbenazine a breakthrough therapy in 2014 given its underlying mechanism and its importance in addressing an unmet need, as there were no available FDA-approved medications indicated for TD. The advantages of valbenazine include once-daily dosing and a rapid onset of effect within 2 weeks of treatment initiation.