Antipsychotics, Atypical:
Comment:
Metoclopramide is a dopamine D2 receptor antagonist and can cause extrapyramidal reactions and tardive dyskinesias. Atypical antipsychotics also increase the risk of these movement disorders, albeit to a lesser extent than phenothiazines. Nonetheless, it is likely that a person taking metoclopramide with an atypical antipsychotic would be at greater risk of extrapyramidal reactions than a person taking either drug alone. Theoretically, one would expect an increased risk of this interaction in patients with low CYP2D6 activity due to genetics or therapy with CYP2D6 inhibitors, since metoclopramide is a CYP2D6 substrate. Also metoclopramide is partially eliminated unchanged in the urine, so patients with severe renal impairment may also be at greater risk.
Class 2: Use Only If Benefit Felt to Outweigh Risk