Resistance nrti

NRTI resistance is well characterized, and the most common mutation is the mutation at viral codon 184, which confers a high degree of resistance to lamivudine and emtricitabine but, more importantly, restores sensitivity to zidovudine and tenofovir. Because cross-resistance and antagonism occur between agents of the same analog class (thymidine, cytosine, guanosine, and adenosine), concomitant use of agents in the same class is contraindicated (for example, zidovudine plus stavudine).