Tarkiainen_2012_Clin.Pharmacol.Ther_92_68

Bioactivation of the antiviral agent oseltamivir to active oseltamivir carboxylate is catalyzed by carboxylesterase 1 (CES1). After the screening of 860 healthy Finnish volunteers for the CES1 c.428G>A (p.Gly143Glu, rs121912777) polymorphism, a pharmacokinetic study with 75 mg oseltamivir was carried out in c.428G>A carriers and noncarriers. Heterozygous c.428GA carriers (n = 9) had 18% larger values of oseltamivir area under the plasma concentration-time curve from 0 h to infinity (AUC(0-infinity)) (P = 0.025) and 23% smaller carboxylate-to-oseltamivir AUC(0-infinity) ratio (P = 0.006) than noncarriers (n = 12). This shows that the CES1 c.428G>A polymorphism impairs oseltamivir bioactivation in humans.