pentobarbital will reduce the extent or effect of parecoxib by impacting hepatic enzyme CYP2C9/ten metabolism. Use Caution/Check.pentobarbital decreases amounts of elvitegravir/cobicistat/emtricitabine/tenofovir DF by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. May well cause lack of virologic reaction and probable res