Vemlidy (tenofovir alafenamide, or TAF) is an antiviral medicine used to treat chronic hepatitis B virus (HBV) infection in adults. It is not an HIV medicine when used alone, although TAF is also found in combination HIV tablets (such as Genvoya, Odefsey, and Symtuza).

TAF is a newer form of tenofovir that works by blocking the reverse transcriptase enzyme in the hepatitis B virus, stopping it from replicating. Compared to the older form of tenofovir (TDF, found in Viread), TAF delivers the active drug directly to liver cells at a much lower plasma dose, resulting in significantly less impact on the kidneys and bones.

Take one 25 mg tablet once daily with food. Food improves the absorption of TAF.

Take at the same time each day. Do not stop without speaking to your doctor. Stopping antiviral treatment for hepatitis B can cause a serious and potentially life-threatening flare of hepatitis B activity.

If you remember within 18 hours of your usual dose time, take it with food immediately. If more than 18 hours have passed, skip that dose and take the next one as scheduled. Never take two doses at once.

Contact your doctor or a poison control centre.

• Store below 30°C in the original container
• Keep the bottle tightly closed
• Keep out of reach of children

Vemlidy is generally well tolerated.

Common side effects:

• Nausea
• Headache
• Fatigue
• Abdominal pain

Compared to older tenofovir (TDF):

• Kidney impact: TAF causes significantly less impact on kidney tubules than TDF. However, kidney function is still monitored periodically
• Bone density: less reduction in bone mineral density than TDF

Serious concern:

• Hepatitis B flare on stopping: if Vemlidy is stopped suddenly, a severe hepatitis B flare can occur, sometimes leading to acute liver failure. Do not stop without medical advice and careful monitoring after stopping

• Strong P-glycoprotein inducers (rifampicin, carbamazepine, St John's Wort): significantly reduce TAF levels. Avoid
• P-glycoprotein inhibitors (ciclosporin): may increase TAF exposure

Tell your doctor about all medicines before making any changes.

How long do I need to take Vemlidy for hepatitis B?

Hepatitis B treatment is often long-term. Unlike hepatitis C, hepatitis B cannot currently be cured in most patients with antiviral treatment alone. Vemlidy suppresses hepatitis B viral replication, reducing liver damage and the risk of cirrhosis and liver cancer, but stopping treatment usually leads to viral rebound. Your doctor will review your treatment regularly and discuss whether stopping is an option based on your immune response (hepatitis B surface antigen status, e antigen status, and antibody responses).

Is Vemlidy safe for the kidneys?

Yes, compared to older tenofovir formulations. Vemlidy delivers TAF to liver cells at a much lower plasma concentration than TDF (tenofovir disoproxil fumarate), which means far less tenofovir reaches the kidneys. Clinical trials have shown significantly less impact on kidney tubule function and bone mineral density compared to Viread. It is the preferred option for patients with pre-existing kidney concerns or bone density issues.

Ace provides accurate and independent information medically reviewed on prescription medications. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment.