American Board of Internal Medicine (ABIM) Certification Practice Exam

What is a common side effect of metoclopramide?

1. Weight gain

2. Hypertension

3. Dystonia and parkinsonism-type movements

4. Severe allergic reactions

The correct answer is: Dystonia and parkinsonism-type movements

Metoclopramide is primarily used as an antiemetic and to facilitate gastric emptying in patients with certain gastrointestinal disorders. One notable side effect of metoclopramide is the development of movement disorders, particularly dystonia and parkinsonism-type movements. This occurs due to its action as a dopamine antagonist, especially impacting the central nervous system. The drug interferes with dopaminergic transmission, which can lead to extrapyramidal symptoms that resemble Parkinson's disease, such as rigidity, bradykinesia, and tremors, as well as acute dystonic reactions. This is an important consideration for clinicians when prescribing metoclopramide, especially in populations more vulnerable to these movement disorders, such as the elderly or those who may already be taking other neuroleptic medications. Monitoring patients for these side effects is crucial, particularly with prolonged use or in higher doses. Understanding this side effect can help guide safe prescribing and patient education.