Nevirapine plasma exposure affects both durability of viral suppression and selection of nevirapine primary resistance mutations in a clinical setting.

The relationship between nevirapine plasma concentrations and the durability of both viral suppression (VS) and selection of nevirapine primary resistance mutations (PRMs) was evaluated. A nevirapine trough concentration (Ctrough) of >4,300 ng/ml was found to predict longer VS. Patients with nevirapine Ctrough s ranging from 3,100 to 4,300 ng/ml had higher probabilities of developing PRMs than those with nevirapine Ctrough s below and above this concentration interval.