Antiviral-resistant infection

Antiviral resistance is suggested by a 1 log₁₀ IU/mL (10-fold) increase in hepatitis B virus DNA above the nadir in a fully treatment-adherent patient. This increase can precede biochemical or histological flares by several months.

Antiviral resistance was a significant problem with older antiviral drugs (lamivudine, adefovir, telbivudine); however, both tenofovir and entecavir have a very high barrier to resistance. Lamivudine should not be used as first-line therapy for chronic hepatitis B, and patients taking lamivudine who develop resistance should have their treatment promptly changed to tenofovir monotherapy. Do not use entecavir in patients with lamivudine-resistant hepatitis B infection because cross-resistance is common.

Patients treated with multiple antiviral drugs over many years can develop complex patterns of antiviral resistance. Advice from a specialist with expertise in the management of hepatitis B is strongly recommended.