How Do Hepatitis B NRTIs Work?

Nucleoside reverse transcriptase inhibitors (NRTIs) are drugs that control the multiplication of the hepatitis B virus (HBV) in the body. NRTIs are used to treat long-term HBV infection in children and adults who are at risk of liver disease. Hepatitis B is a vaccine-preventable liver infection caused by HBV. Hepatitis B is transmitted through contact with blood, semen, or other body fluids. The virus transmission can happen through sexual contact; sharing needles, syringes, or other drug-injection equipment; or from mother to baby at birth.

The antiviral drugs (NRTIs) approved by the Food and Drug Administration for the treatment of HBV target the enzyme, reverse transcriptase (RT or P gene product) which is crucial for HBV to reproduce in the body. NRTIs competitively inhibits HBV DNA polymerase, cause chain termination, and stop further DNA replication, which reduces the viral DNA synthesis. As a result, HBV viral replication is inhibited, and new HBV viral components are not formed.

NRTIs used against HBV are:

• Adefovir dipivoxil, a prodrug of adefovir
• Telbivudine is a synthetic thymidine β-L-nucleoside analog.
• Tenofovir alafenamide is a prodrug of tenofovir.

NRTIs are used to treat:

• Chronic type B hepatitis
• Compensated liver disease
• Inhibition of HIV/AIDS

Side effects associated with hepatitis B NRTIs include:

• Headache
• Diarrhea
• Nausea
• Abdominal pain
• Dyspepsia (indigestion)
• Asthenia (general weakness)
• Muscle weakness
• Swelling and pain in the joint
• Cough
• Increased serum creatinine
• Hypophosphatemia (low phosphate levels in the blood)
• Pancreatitis (inflammation of the pancreas)
• Peripheral neuropathy (damage to peripheral nerves which causes numbness)
• Angioedema (swelling of face, tongue, and throat due to accumulation of fluid)
• Severe exacerbation of hepatitis B
• Nephrotoxicity (reduced renal function because of the toxic nature of the drug)
• Severe hepatomegaly (enlargement of the liver) with steatosis (fat build-up in liver cells)
• Lactic acidosis (high levels of lactic acid in the blood)
• Rhabdomyolysis (damage to the muscles)

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of hepatitis B NRTIs include:

• Adefovir, adefovir dipivoxil (Hepsera)
• Telbivudine (Tyzeka)
• Tenofovir AF (Vemlidy)