41 Medication-Induced Movement Disorders

Clinical Vignette

A 57-year-old woman with history of chronic nausea and concomitant use of antiemetic medications presented for evaluation of slowness and tremor. She had been followed by a gastroenterologist for the past 3 years for her nausea. No specific mechanism was identified to explain her symptoms; treatment was initiated with various antinausea medications. Approximately 1.5 years ago, metoclopramide was initiated; it was continued daily. This led to significant improvement of her nausea. Her past medical history was not otherwise of note.

One year ago, she began to note that both hands were shaking and her dexterity diminished, particularly with her handwriting becoming smaller and progressively telescoping. Her family also noticed that she had developed facial masking, a shuffling gait, and a hunched posture. On occasion, her speech had an indistinct and low volume. There was no family history of Parkinson disease or other neurologic conditions. She denied any prior toxic exposure.

Neurologic examination revealed facial masking; hypophonic speech; mild perioral tremor; symmetric generalized bradykinesia and rigidity; a bilateral 5-Hz frequency postural as well as action hand tremor; and a slow, shuffling parkinsonian gait. The diagnosis of drug-induced parkinsonism was suspected. Metoclopramide was discontinued. She had complete resolution of her symptoms and was normal when seen 6 months later.

There are a large number of pharmaceutical agents with the potential to cause a movement disorder (Table 41-1). These medications primarily interfere with dopaminergic transmission within the basal ganglia (levodopa, dopamine agonists, dopamine receptor–blocking agents [DRBs]). Other classes of these movement disorder–inducing agents do not have as precisely defined biochemical mechanisms. These medications include central nervous system (CNS) stimulants, anticonvulsants, tricyclic antidepressants, and estrogens. From a clinical perspective, the medications most commonly responsible for iatrogenic movement disorders are the various neuroleptics and pharmacologic agents that block or stimulate dopamine receptors.

Table 41-1 Types of Drug-Induced Movement Disorders and Responsible Medications

Syndrome	Responsible Medication
Postural tremor	Sympathomimetics Levodopa Amphetamines Bronchodilators Tricyclic antidepressants Lithium carbonate Caffeine Thyroid hormone Sodium valproate Antipsychotics Hypoglycemic agents Adrenocorticosteroids Alcohol withdrawal Amiodarone Cyclosporin A Others
Acute dystonic reactions	Antipsychotics Metoclopramide Antimalarial agents Tetrabenazine Diphenhydramine Mefenamic acid Oxatomide Flunarizine and cinnarizine
Akathisia	Antipsychotics Metoclopramide Reserpine Tetrabenazine Levodopa and dopamine agonists Flunarizine and cinnarizine Ethosuximide Methysergide
Parkinsonism	Antipsychotics Metoclopramide Reserpine Tetrabenazine Methyldopa Flunarizine and cinnarizine Lithium Phenytoin Captopril Alcohol withdrawal MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) Other toxins (manganese, carbon disulfide, cyanide) Cytosine arabinoside
Chorea, including tardive and orofacial dyskinesia	Antipsychotics Metoclopramide Levodopa Direct dopamine agonists Indirect dopamine agonists and other catecholaminergic drugs Anticholinergics Antihistaminics Oral contraceptives Phenytoin Carbamazepine Ethosuximide Phenobarbital Lithium carbonate Methadone Benzodiazepines Only gold members can continue reading. Log In or Register to continue Share this: Click to share on Twitter (Opens in new window) Click to share on Facebook (Opens in new window) Related Related posts: Wilson Disease Major Depression Other Neuromuscular Transmission Disorders Coma, Vegetative State, Brain Death, and Increased Intracranial Pressure Lumbar Radiculopathy Subarachnoid Hemorrhage Stay updated, free articles. Join our Telegram channel Tags: Netters Neurology Jun 4, 2016 \| Posted by admin in NEUROLOGY \| Comments Off on Medication-Induced Movement Disorders Full access? Get Clinical Tree Get Clinical Tree app for offline access Get Clinical Tree app for offline access