Tenofovir

Key facts

• Tenofovir is used with other antiretrovirals to treat HIV infection, on its own or in combination to prevent HIV infection (PrEP), and to treat chronic hepatitis B.
• It is taken once daily as part of a combination tablet or regimen, with or without food depending on the formulation.
• Tenofovir can reduce kidney function and bone density over time; your prescriber will check kidney function periodically and may check bone density if you are at higher risk.
• If you have hepatitis B and stop tenofovir, your liver disease can flare up severely, sometimes life-threateningly; never stop it without medical supervision, and expect liver monitoring for several months afterwards.

What tenofovir treats

Tenofovir treats HIV-1 infection as part of a combination antiretroviral regimen, and treats chronic hepatitis B infection by suppressing the virus and reducing liver damage. It is also used, alone or combined with emtricitabine, to reduce the risk of acquiring HIV in people at ongoing risk (pre-exposure prophylaxis, or PrEP). It does not cure HIV or hepatitis B.

How tenofovir works

Tenofovir is a nucleotide analogue. Cells convert it to an active form that HIV's reverse transcriptase enzyme, or the hepatitis B virus's own polymerase, mistakes for a natural building block of DNA. When the enzyme incorporates it into the growing viral DNA chain, that chain stops extending, so the virus cannot complete new copies of its genetic material.

Before you take it

• Tell your prescriber about any kidney disease, bone disease (such as osteoporosis), or history of fractures, since tenofovir can worsen these.
• Tell your prescriber if you have hepatitis B, so liver flares after stopping the drug can be anticipated and monitored.
• Combining tenofovir with certain other medicines that also affect the kidneys, including some other antiretrovirals and some pain relievers, increases the risk of kidney harm.
• If you are pregnant or breastfeeding, discuss the risks and benefits with your prescriber.

Side effects

Common effects are nausea, diarrhoea, and headache.

Stop and seek urgent medical care for any of these:

• Reduced urination, swelling of the legs, or unusual tiredness, which can signal kidney problems.
• Bone pain or a fracture from a minor injury.
• Yellowing of the skin or eyes, dark urine, or worsening abdominal pain, especially after stopping tenofovir if you have hepatitis B.
• Unusual muscle weakness with rapid breathing, which can signal a rare but serious build-up of lactic acid.

Safety essentials

• Kidney function and bone density are monitored during tenofovir treatment, and stopping the drug abruptly if you have hepatitis B can trigger a severe liver flare; both points are the single most important safety facts about this medicine and the reason you should never adjust or stop it without medical advice.
• Your prescriber will check kidney function with blood and urine tests periodically, more often if you have other risk factors for kidney disease.
• Take tenofovir exactly as prescribed alongside your other medicines; missed doses in HIV treatment or PrEP reduce its effectiveness.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.