Tardive tremor

Tardive Syndrome Is a Mysterious Phenomenon with Different Clinical Manifestations-Review

Tardive syndrome (TS) refers to persistent hyperkinetic, hypokinetic, and sensory complaints appearing after chronic neuroleptics and other dopamine receptor-blocking agents (DRBAs). It is defined as involuntary movements, often rhythmic, choreiform, or athetoid, involving the tongue, face, extremities, and sensory urges such as akathisia and lasts for a few weeks. TS develops in association with neuroleptic medication usage for a few months at least. There is usually a delay between the initiation of the causative drug and the onset of abnormal movements. However, it was soon noted that TS can also develop early, even days or weeks after DRBAs begin. However, the longer the exposure, the greater the risk of developing TS. Tardive dyskinesia, dystonia, akathisia, tremor, and parkinsonism are frequent phenomenologies of this syndrome.

The selective 5-HT 1A receptor agonist, NLX-112, overcomes tetrabenazine-induced catalepsy and depression-like behavior in the rat

Tetrabenazine, a preferential inhibitor of the vesicular monoamine transporter type 2, depletes the brain monoamines dopamine, serotonin and norepinephrine. Tetrabenazine and deutetrabenazine (Austedo ®) are used to treat chorea associated with Huntington's disease. However, both compounds are known to aggravate Parkinsonism and depression observed in Huntington's disease patients. NLX-112 (a.k.a. befiradol/F13640) is a highly selective, potent and efficacious serotonin 5-HT 1A agonist. In animal models, it has robust efficacy in combating other iatrogenic motor disorders such as L-DOPA-induced dyskinesia and has marked antidepressant-like activity in rodent tests. In the present study, we investigated, in rats, the efficacy of NLX-112 to counteract tetrabenazine-induced catalepsy (a model of Parkinsonism) and tetrabenazine-induced potentiation of immobility in the forced swim test (FST, a model to detect antidepressant-like activity). The prototypical 5-HT 1A agonist, (±)8-OH-DPAT, and the 5-HT 1A partial agonist/dopamine D2 receptor blocker, buspirone, were used as comparators. Both NLX-112 and (±)8-OH-DPAT (0.16-2.5 mg/kg p.o. or s.c., respectively) abolished catalepsy induced by tetrabenazine (2 mg/kg i.p.). In comparison, buspirone (0.63-5.0 mg/kg p.o.) was ineffective and even tended to potentiate tetrabenazine-induced catalepsy at 0.63 mg/kg. In the FST, NLX-112 and (±)8-OH-DPAT (0.63 mg/kg) strongly reduced immobility when administered alone but also significantly opposed potentiation of immobility induced by tetrabenazine (1.5 mg/kg i.p.). Buspirone (0.63 and 2.5 mg/kg p.o.) had no effect by itself or against tetrabenazine. These results strongly suggest that selective and highly efficacious 5-HT 1A agonists, such as NLX-112, may be useful in combating tetrabenazine-induced Parkinsonism and/or depression in Huntington's disease patients.

Tetrabenazine

BACKGROUND

Tetrabenazine (TBZ) depletes presynaptic dopamine in the CNS. It has been found to be beneficial in hyperkinetic movement disorders without carrying the extrapyramidal side effects that are characteristic of neuroleptics.

OBJECTIVE

To summarize current knowledge on the use of TBZ and draw conclusions about its efficacy and safety.

METHODS

PubMed literature searches using the term 'tetrabenazine' were carried out for the period prior to May 2009. Additional relevant studies referenced by these publications were included.

CONCLUSIONS

Both short- and long-term studies have consistently yielded favorable results for the use of TBZ in the treatment of hyperkinetic movement in terms of efficacy and safety. TBZ is most effective in reducing chorea (including Huntington's disease associated chorea), tic associated with Tourette's syndrome and tardive dyskinesias. Furthermore, TBZ might also have potential for use in other hyperkinetic disorders (e.g., myoclonus and dystonia), for which future clinical trials are needed.

Tetrabenazine in the treatment of hyperkinetic movement disorders

Tetrabenazine, a dopamine-depleting agent first synthesized half a century ago, was initially developed for the treatment of schizophrenia. Although psychotic disorders have since been treated more successfully with other neuroleptic medications, many studies have shown this drug to be effective in the treatment of hyperkinetic movement disorders (hyperkinesias). Hyperkinesias are neurologic disorders characterized by abnormal involuntary movements such as chorea associated with Huntington's disease, tics in Tourette's syndrome and stereotypies in tardive dyskinesia. Recently, clinical trials investigating tetrabenazine for the treatment of chorea associated with Huntington's disease found the drug to be safe and efficacious, making approval by the US Food and Drug Administration for this indication a distinct possibility.

Tetrabenazine Treatment in Movement Disorders

Tetrabenazine (TBZ) is a catecholamine depletor used for the treatment of a variety of movement disorders. The purpose of this study was to assess the efficacy of TBZ in a retrospective chart review in 3 tertiary care movement disorders centers over long-term treatment. Of 150 patients to whom TBZ was prescribed, 118 were followed up and assessed using the Clinical Global Impression of Change (CGIC), (-3 to +3), a composite grade from a patient and caregiver scale over variable periods. The patients had a variety of hyperkinetic movement disorders including dystonia (generalized and focal: axial, Meige syndrome, torticollis, blepharospasm, bruxism), Huntington disease (HD) or other choreas, tardive dyskinesia (TD) or akathisia, and Tourette syndrome. Mean patient age was 48.8 +/- 18.7 years; 48 were men (40.7%) with a mean disease duration of 93 months. The mean follow-up time was 22 months and the mean TBZ dose was 76.2 +/- 22.5 mg/d (median 75 mg, range 25-175 mg/d). The mean CGIC score was +1 (mild improvement). The group of patients who scored +3 on the CGIC (very good improvement) represented 18.6% (n = 22) of all patients. They had HD or other types of chorea 7.6% (n = 9), facial dystonia/dyskinesia (n = 7, 5.9%), 1 with TD, 2 with trunk dystonia, 2 with Tourette syndrome, and 1 with tardive akathisia. This group had the longest treatment duration and received a mean TBZ dose of 70.5 mg/d (median 75 mg/d) for a mean of 25.4 +/- 21.3 months. The report concludes that TBZ is a moderately effective treatment of a large variety of hyperkinetic movement disorders, with excellent effects in a subgroup with chorea and facial dystonia/dyskinesias.

Tardive tremor due to metoclopramide

Tardive tremor is a very uncommon neuroleptic-induced tardive syndrome which was initially described in five patients by Stacy and Jankovic (Stacy and Jankovic, Mov Disord 1992;7:53-57). Since then, there have been only three additional case reports attesting to the apparent rarity of this condition, although it is unknown whether other unreported cases have been observed. We describe a patient with persistent tardive tremor that was associated with tardive dyskinesia, who closely resembles previously reported cases.

Phenomenology and treatment of tremor disorders

Tremor is classified according to anatomic distribution among body parts, and by frequency and amplitude during rest, postural maintenance, movement, intention, and the performance of specific tasks. Key historical features include age at onset, progression over time, family history, exacerbating and remitting factors and behaviors, response to alcohol and medications, and additional neurological signs and symptoms. Accurate diagnosis is a critical factor in predicting the natural history and response to treatment.