Trough plasma concentrations of non-nucleoside reverse transcriptase inhibitor and protease inhibitor. The box plot provides a five-point summary of the data: minimum, 1st quartile, median, 3rd quartile and maximum. NVP, Nevirapine; EFV, efavirenz; LPV, lopinavir; NFV, nelfinavir; APV, amprenavir; ATV, atazanavir; SQV, saquinavir; IDV, indinavir