Detection times of pregabalin in urine after illicit use: when should a positive specimen be considered a new intake?

BACKGROUND: Pregabalin has an abuse potential and is occasionally used as a recreational drug. To draw the right conclusions regarding new intake of pregabalin in situations of repeated urinary drug testing, the knowledge of its disappearance rate in urine is essential. METHODS: One healthy male volunteer took a single oral dose of pregabalin at 2 occasions, first 75 mg and thereafter 150 mg. All urine was collected in 8-hour portions for 5 days and analyzed for pregabalin. A systematic search for literature describing concentrations of pregabalin in urine was performed, and the results from these studies were interpreted on the basis of the findings from the healthy volunteer. RESULTS: In the healthy volunteer, specimens remained positive for 56 hours after intake of 75 mg and for 64 hours after intake of 150 mg. Urinary elimination half-lives based upon creatinine-normalized concentrations were 5.7-5.9 hours. The systematic literature search revealed only 1 article describing urinary concentrations of pregabalin. In that study, including 4799 urinary samples, the median concentration was not higher than the initial concentration found in the healthy volunteer. By applying a urinary elimination half-life of 6 hours on that material, at least 50% would be expected to have negative urine specimens within 3 days and a total of 5 days would be needed to achieve negative urine specimens in the subject with the maximum urinary concentration measured. CONCLUSION: In subjects with normal renal function, it seems highly unlikely that a urine specimen should remain positive for pregabalin for more than 5-6 days after intake.