Lack of impairment due to confirmed codeine use prior to a motor vehicle accident: role of pharmacogenomics.

BACKGROUND We examined forensic serum toxicology and pharmacogenomics data from a woman on codeine shortly before she caused a motor vehicle accident. METHODS A woman driving erratically collided with a parked car of a highway seriously injuring 2 men working to repair the parked vehicle. The woman tested positive for codeine, acetaminophen and barbital. She had been taking these medications for 20 years due to migraine headache. Serum toxicology and genotype analysis for cytochrome P450, UDP glucuronosyltransferase, and other metabolizing enzymes were measured. RESULTS The woman was tried and convicted of driving under the influence resulting in bodily harm and was sentenced to 6 years. Toxicology results on peripheral blood showed a total and free codeine of 840 and 348 μg/L, respectively, and total morphine of 20 μg/L (17, 3, and 0 μg/L for morphine-3-glucuronide, morphine-6-glucuronide, and free morphine, respectively). She was heterozygous for CYP 2D6 *2/*4 (extensive/poor metabolism) and heterozygous for UGT 2B7 *1/*2 (extensive/ultra-rapid metabolism). The woman was also taking fluoxetine and bupropion which are strong inhibitors of CYP 2D6. CONCLUSIONS Based on her genotype and phenotype and reports by the arresting officer, we suggest that the subject in question was not intoxicated by opiates at the time of her motor vehicle accident and may have been falsely incarcerated.