Effect of varenicline on tardive dyskinesia: a pilot study

STANLEY N. CAROFF ^{1, 2*}, ALISA R. GUTMAN ¹, JOHN NORTHROP ¹, SHIRLEY H. LEONG ¹, ROSALIND M. BERKOWITZ ¹, E. CABRINA CAMPBELL ^{1, 2}

¹Michael J. Crescenz VA Medical Center , ²University of Pennsylvania Perelman School of Medicine

Received: July 6, 2020; Accepted: July 8, 2020; Published online: July 8, 2020.

Abstract: Objectives: Although evidence implicates striatal cholinergic impairment as a mechanism underlying tardive dyskinesia, trials of nonspecific cholinergic agents have been inconclusive. As a partial agonist at specific nicotinic receptor subtypes, varenicline reduces drug-induced dyskinesias in animal models suggesting promise as a treatment for tardive dyskinesia.
Methods: Three schizophrenia patients with tardive dyskinesia who were smokers underwent an open trial of varenicline. After a 2-week baseline, subjects received varenicline 1mg twice daily. Changes from baseline on the Abnormal Involuntary Movement Scale were measured after a 4-week varenicline stabilization period, and 6 weeks after the smoking quit date in one patient.

Results: Varenicline had no effect on mean Abnormal Involuntary Movement Scale scores after 4 weeks. Although smoking decreased after 4 weeks on varenicline and diminished further in one patient after 10 weeks, this also appeared to have no effect on ratings of tardive dyskinesia.

Conclusion: In contrast to animal models, no significant change in tardive dyskinesia occurred in response to varenicline replacement in three schizophrenia patients. Further investigations of cholinergic mechanisms in tardive dyskinesia are worthwhile as agents for specific cholinergic targets become available for treatment. In addition, treatment trials of tardive dyskinesia should control for smoking status, while patients on antipsychotics receiving nicotine replacement therapies for smoking should be studied further for changes in movement.; Keywords: tardive dyskinesia, antipsychotic agents, smoking cessation, parkinsonian disorders, varenicline, acetylcholine, movement disorders, vesicular monoamine transport inhibitor proteins

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