A 58-year-old woman started on metoclopramide 30 mg daily for diabetic gastroparesis 2 months ago develops slowness of movement, bilateral restlessness of the legs, and reduced arm swing. Examination shows bradykinesia and cogwheel rigidity without tremor. CT head is normal. What is the most appropriate next step?
- A Stop metoclopramide and substitute domperidone ✓
- B Start levodopa-carbidopa and continue metoclopramide
- C Start pramipexole
- D Start amantadine
Correct answer: A. Stop metoclopramide and substitute domperidone
Explanation
Metoclopramide crosses the blood-brain barrier and blocks striatal D2 receptors, causing drug-induced parkinsonism, which is usually symmetrical, tremor-predominant absent, and reversible on withdrawal. The correct action is to stop the offending agent and switch to a prokinetic that does not cross the blood-brain barrier, such as domperidone. Starting dopaminergic therapy masks the picture unnecessarily and is not indicated before withdrawal is attempted.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.