Ved cellekultur var potensen af efavirenz over for virusvarianter med aminosyresubstitutioner på positionerne 48, 108, 179, 181 eller 236 i RT eller varianter med aminosyresubstitutioner i proteasen lig den, der sås over for vildtype- virusstammer.
Resistance: the potency of efavirenz in cell culture against viral variants with amino acid substitutions at positions 48, 108, 179, 181 or 236 in RT or variants with amino acid substitutions in the protease was similar to that observed against wild type viral strains.