Pregabalin: Medlineplus Drug Info Following a dose of radiolabeled pregabalin, roughly 90% of the administered dose was recovered in the urine as unchanged pregabalin. The N-methylated spinoff of pregabalin, the most important metabolite of pregabalin found in urine, accounted for 0.9% of the dose. In preclinical studies, pregabalin (S-enantiomer) didn’t endure racemization to the R-enantiomer