Drugs that Cause Movement Disorders

• Patient stress and anxiety levels, as both of these can exacerbate DIMD symptoms;
• Patient drug history; and
• Demographic information. Older women are most likely to develop tardive dyskinesia. Young men more commonly experience dystonic reactions. The elderly are at higher risk for Parkinsonism and akathisia.

Clinicians must watch for DIMD in any patient who has taken antipsychotics. Symptoms can occur within hours to days (acute), weeks (subacute) or even months to years (tardive) following exposure.

The Agents

Causative DRBAs include:

• Haloperidol;
• Thioridazine;
• Perphenazine;
• Droperidol;
• Metoclopramide;
• Prochlorperazine; and
• Promethazine.

DIMDs can also occur from:

• Lithium, which can cause tremors or chorea;
• Stimulants (e.g., amphetamines), which can cause tremor, tics, dystonia, and dyskinesia;
• Selective-serotonin reuptake inhibitors (SSRIs), which can cause tremors, akathisia, and possible dyskinesia, dystonia, and Parkinsonism;
• Tricyclic antidepressants (TCAs) (e.g., amitriptyline, nortriptyline, etc), which can cause myoclonus and tremors;
• Valproic acid, which causes tremors; and
• Cyclosporine A, which was implicated in one study as causing tremors and Parkinsonism.6

Management

For neuroleptics, withdrawal of the offending agent may lead to partial improvement in about half of patients. The outcome, of course, depends on the DIMD.

Early detection of TD is important to improve remission rates, which are inversely related to the disorder’s duration and severity. To treat, gradually taper the patient off the medication. It may take as long as two years after discontinuation for the condition to resolve itself. Continually re-evaluate how much a patient needs this agent. There may be another that’s just as effective but with a lower TD incidence. 7

Treat acute dystonic reactions with a short course of a potent antimuscarinic agent such as oral, intravenous (IV), or intramuscular benztropine, or diphenhydramine. If the patient’s reaction is life-threatening, use IV administration of an antimuscarinic agent and supportive measures. In some cases, you can use benzodiazepines in place of antimuscarinic agents. For tardive dystonia, prevention is the most important treatment since few pharmacologic treatments have proven efficacy.

Prevention also is the key to managing akathisia. To prevent this manifestation, prescribe atypical antipsychotics or use a standardized dose titration to avoid excessive dose escalation. In high-risk patients, consider prophylactic treatment with diphenhydramine or benztropine. Other potentially useful agents include benzodiazepines, propranolol, or cyproheptadine. For acute reactions, remove the causative agent.

Treat drug-induced Parkinsonism by withdrawing the causative agent or reducing the dose, switching to an atypical antipsychotic (if neuroleptic-induced), and possibly prescribing a trial of amantadine, an antimuscarinic agent, a dopamine agonist, or levodopa.

Though antiemetics and conventional antipsychotics are most commonly implicated, other agents also cause DIMDs. To prevent and treat these disorders, clinicians need to be particularly aware of the causative agents and symptoms. TH

Michele B. Kaufman, PharmD, BSc, RPh, is a registered pharmacist based in New York City.

References

1. Chen JJ. Drug-induced Movement Disorders. Journal of Pharmacy Practice. 2007; 20(6):415-429.
2. Zacher JL, Hatchett AD. Aripiprazole-induced movement disorder. Am J Psychiatry. 2006;163:160-161[letter].
3. Sajbel TA, Cheney EM, DeQuardo JR. Aripiprazole-associated dyskinesia. Ann Pharmacother. 2005;39:200-201[letter].
4. Lee PE, Synkora K, Gill SS., et al. Antipsychotic medications and drug-induced movement disorders other than Parkinsonism: A population-based cohort study in older adults. J Am Geriatr Soc. 2005;53:1374-1379.
5. Munhoz RP, Teive HAG, Germiniani FMB et al. Movement disorders secondary to long-term treatment with cyclosporine A. Arq Neuropsiquiatr. 2005;63(3-A)L592-596.
6. Vernon, Gwen M. Drug-Induced & Tardive Movement Disorders. National Alliance for the Mentally Ill, July 2001.www.namiscc.org/newsletters/July01/tardive.htm