Tetrabenazine, a monoamine-depleting drug used in the treatment of hyperkinetic movement disorders.
BACKGROUND
Few drugs are available for the management of hyperkinetic movement disorders such as the dystonias, choreas, dyskinesias, and tics. Those that are available (primarily neuroleptics) are associated with a wide range of potentially serious adverse effects, including induction of tardive movement disorders. Tetrabenazine (TBZ) is a monoamine-depleting agent initially studied in the 1950s and currently approved by the US Food and Drug Administration for the treatment of chorea in Huntington's disease.


OBJECTIVE
This article reviews the chemistry, pharmacology, pharmacokinetics, therapeutic use, tolerability, drug-interaction potential, and dosing and administration of TBZ.


METHODS
MEDLINE was searched (1950-February 2010) for English-language articles investigating any aspect of TBZ. Search terms included tetrabenazine, Ro 1-9569, Nitoman, benzoquinolizines, and reserpine. The reference lists of the identified articles were searched for other pertinent publications, particularly those that were not indexed in the 1950s and 1960s.


RESULTS
In the search for a chemical compound that was simpler than reserpine while preserving reserpine-like psychotropic activity, TBZ was identified in the 1950s as one member of a large group of benzoquinolizine derivatives. TBZ acts by depletion of the monoamines serotonin, norepinephrine, and dopamine in the central nervous system (CNS). It does this by reversibly inhibiting vesicle monoamine transporter type 2 and thus preventing monoamine uptake into presynaptic neurons. Clinical studies suggest that TBZ may have therapeutic applications in a wide range of hyperkinetic movement disorders. TBZ has been associated with numerous adverse effects, some of them serious and potentially fatal; these include parkinsonism, other extrapyramidal symptoms (particularly akathisia), depression and suicidality, neuroleptic malignant syndrome, and sedation. TBZ is subject to important drug-drug interactions with inhibitors and inducers of cytochrome P450 (CYP) 2D6, reserpine, and lithium. It is one of very few drugs whose dosing is based, in part, on the results of genotyping (in its case, genotyping for CYP2D6 metabolizer status).


CONCLUSIONS
TBZ is a complicated drug in terms of its mechanism of action and its activities against the 3 major monoamines in the CNS, making it difficult to predict its efficacy and tolerability in patients with hyperkinetic movement disorders. It is associated with numerous adverse effects and several important drug-drug interactions. Much work remains to be done to determine the therapeutic potential of TBZ in the treatment of hyperkinetic movement disorders.
Guay
David R P
DR
Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, USA. guayx001@umn.edu
D018759:Adrenergic Uptake Inhibitors / Q000008:administration & dosage / Q000009:adverse effects; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002986:Clinical Trials as Topic; D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics / Q000378:metabolism; D003863:Depression / Q000139:chemically induced; D004298:Dopamine / Q000378:metabolism; D004347:Drug Interactions / Q000235:genetics; D005838:Genotype; D006801:Humans; D006816:Huntington Disease / Q000188:drug therapy* / Q000378:metabolism; D006948:Hyperkinesis / Q000188:drug therapy; D008875:Middle Aged; D009069:Movement Disorders / Q000188:drug therapy / Q000378:metabolism; D009459:Neuroleptic Malignant Syndrome; D010302:Parkinson Disease, Secondary / Q000139:chemically induced; D011807:Quinolizines / Q000494:pharmacology; D012110:Reserpine / Q000008:administration & dosage / Q000009:adverse effects; D012701:Serotonin / Q000378:metabolism; D013747:Tetrabenazine / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D050493:Vesicular Monoamine Transport Proteins / Q000037:antagonists & inhibitors; D055815:Young Adult
D018759:Adrenergic Uptake Inhibitors; D011807:Quinolizines; D050493:Vesicular Monoamine Transport Proteins; C115706:YNS 15P; D012701:Serotonin; D012110:Reserpine; D019389:Cytochrome P-450 CYP2D6; D004298:Dopamine; D013747:Tetrabenazine