<unk>  (Epivir) is indicated in combination with other antiretroviral agents for the treatment of HIV‑1 infection.<unk>  (Epivir HBV) is indicated for the treatment of chronic hepatitis B virus infection associated with evidence of hepatitis B viral replication and active liver inflammation.<unk>  has been used for treatment of chronic hepatitis B at a lower dose than for treatment of HIV/AIDS. It improves the seroconversion of e-antigen positive hepatitis B and also improves histology staging of the liver. Long-term use of<unk>  leads to emergence of a resistant hepatitis B virus (YMDD) mutant. Despite this,<unk>  is still used widely as it is well tolerated. Resistance In HIV, high level resistance is associated with the M184V/I mutation in the reverse transcriptase gene as reported by Raymond Schinazi's group at Emory University. GlaxoSmithKline claimed that the M184V mutation reduces "viral fitness", because of the finding that continued<unk>  treatment causes the HIV viral load to rebound but at a much lower level, and that withdrawal of<unk>  results in a higher viral load rebound with rapid loss of the M184V mutation; GSK therefore argued that there may be benefit in continuing<unk>  treatment even in the presence of high level resistance, because the resistant virus is "less fit". The COLATE study has suggested that there is no benefit to continuing<unk>  treatment in patients with<unk>  resistance. A better explanation of the data is that<unk>  continues to have a partial anti-viral effect even in the presence of the M184V mutation. In hepatitis B,<unk>  resistance was first described in the YMDD (tyrosine-methionine-aspartate-aspartate) locus of the HBV reverse transcriptase gene. The HBV reverse transcriptase gene is 344 amino acids long and occupies codons 349 to 692 on the viral genome. The most commonly encountered resistance mutations are M204V/I/S. The change in amino acid sequence from YMDD to YIDD results in a 3.2 fold reduction in the error rate of the reverse transcriptase, which correlates with a significant growth disadvantage of the virus. Other resistance mutations are L80V/I, V173L and L180M.
Lamivudine
Telbivudine
Sorivudine
Saquinavir
Fosamprenavir
Abacavir
Maribavir
Indinavir