Acute dystonic reaction to metoclopramide in patients carrying homozygous cytochrome P450 2D6 genetic polymorphisms.

Author(s): van der Padt A, van Schaik RH, Sonneveld P

Affiliation(s): Department of Internal Medicine, Ikazia Hospital, Rotterdam, the Netherlands. annemiekevanderpadt@yahoo.com

Publication date & source: 2006-05, Neth J Med., 64(5):160-2.

Publication type: Case Reports

BACKGROUND: Extrapyramidal syndromes (EPS) are clinically relevant side effects of metoclopramide which are often not anticipated. PATIENTS AND METHODS: Two patients who received metoclopramide developed an acute dystonic reaction. Symptoms disappeared after biperiden or trihexyphenidyl were given. Molecular analysis of the CYP2D6 gene was performed using a PCR-based method. RESULTS: Both patients were homozygous for inactive CYP2D6 alleles (CYP2D6*4/*4 and CYP2D6*4/*5), which are associated with slow drug metabolism. CONCLUSION: Metoclopramide-induced acute dystonic reactions may occur in patients carrying a CYP2D6 genetic polymorphism.