Uses

Tenofovir disoproxil fumarate (TDF) is a nucleotide reverse transcriptase inhibitor indicated for the treatment of HIV-1 infection in adults and pediatric patients (in combination with other antiretroviral agents) and for pre-exposure prophylaxis (PrEP) in at-risk adults and adolescents to reduce the risk of sexually acquired HIV-1. It is also used for chronic hepatitis B treatment.

Do not use if

TDF for HIV-1 PrEP is contraindicated in individuals with unknown or positive HIV-1 status, as monotherapy can lead to resistance. Use with caution in patients with renal impairment; avoid if eGFR is below recommended thresholds.

Side effects

Common side effects include nausea, diarrhea, vomiting, and headache. Serious effects include new onset or worsening renal impairment (including Fanconi syndrome), decreased bone mineral density, lactic acidosis with hepatic steatosis, and immune reconstitution inflammatory syndrome.

Warnings

Severe acute exacerbations of hepatitis B have occurred in HBV-coinfected patients who discontinued TDF. Monitor hepatic function closely for several months after stopping therapy. Risk of drug resistance if used as PrEP in undiagnosed HIV-positive individuals.

How it works

TDF is a prodrug that is converted intracellularly to tenofovir diphosphate, a competitive inhibitor of HIV-1 reverse transcriptase. It incorporates into viral DNA, causing chain termination and inhibiting HIV replication. It also inhibits hepatitis B virus DNA polymerase.

Storage

Store below 25°C. Keep in original container tightly closed. Protect from moisture.