A patient with Parkinson's disease is prescribed selegiline. Its mechanism and a specific dietary interaction to avoid are:

• A Selective irreversible MAO-A inhibitor; avoid tyramine-containing foods
• B Non-selective MAO inhibitor; requires full tyramine dietary restriction as with phenelzine
• C Selective irreversible MAO-B inhibitor; tyramine restriction is not required at therapeutic doses ✓
• D COMT inhibitor; avoid catechol-rich foods such as green tea

Explanation

Selegiline (deprenyl) selectively and irreversibly inhibits MAO-B, which is the predominant MAO isoform in the striatum and is responsible for dopamine catabolism; this prolongs the action of dopamine in the basal ganglia. At standard anti-Parkinsonian doses (5–10 mg/day), selectivity for MAO-B is maintained, so tyramine ('cheese reaction') is not a concern because intestinal and hepatic MAO-A remains functional. At higher doses, selectivity is lost. Rasagiline is a newer, more selective MAO-B inhibitor.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.