Participants taking tenofovir/emtricitabine (Truvada) for pre-exposure prophylaxis (PrEP) in two major studies experienced modest declines in kidney function that were associated with higher tenofovir drug levels and older age, according to studies presented in a poster discussion session entitled “It’s complicated: renal function and STIs in PrEP users” at the Conference on Retroviruses and Opportunistic Infections (CROI 2016) last week in Boston. Together, these findings indicate that while Truvada PrEP is safe for most people, ongoing kidney function monitoring is important to promptly catch any problems that may occur.
Tenofovir disoproxil (Viread, also in the Atripla, Eviplera or Complera, and Stribild single-tablet regimens) has been used in HIV treatment for more than a decade and is generally considered safe and well-tolerated, but it can cause kidney damage and bone loss in some people.
For this reason, regular kidney function tests are recommended for people taking Truvada for PrEP and those with pre-existing kidney problems are advised not to use it. The US product label for Truvada states that it should not be used for PrEP in people with creatinine clearance below 60 ml/min, and if a decrease is observed providers should “evaluate potential causes and re-assess potential risks and benefits of continued use.”
Reports to date from PrEP clinical trials – which tried to exclude people with known kidney impairment – have not revealed notable kidney problems. But sometimes uncommon toxicities only show up after many more people are using a drug.