Tenofovir disoproxil fumarate (TDF) is an oral prodrug of tenofovir, a nucleotide reverse transcriptase inhibitor (NRTI). It is a cornerstone of antiretroviral therapy (ART) for HIV-1 infection and a first-line agent for chronic Hepatitis B virus (HBV) infection. In the Indian context, it is widely used, cost-effective, and available under the National AIDS Control Programme (NACP). It requires careful monitoring of renal function and bone mineral density due to potential adverse effects.
Adult: HIV-1 or HBV: 300 mg orally once daily, with or without food (better with food).
Note: Swallow tablet whole with water. Can be taken with or without food, but a high-fat meal increases bioavailability. For PrEP, must be confirmed HIV-negative before initiation and regularly during use. Do not use as monotherapy for HIV.
Tenofovir disoproxil fumarate is a diester prodrug of tenofovir. After oral administration, it is converted to tenofovir, which is taken up by cells and phosphorylated by cellular enzymes to its active form, tenofovir diphosphate. Tenofovir diphosphate is a competitive inhibitor of viral reverse transcriptase (HIV) and DNA polymerase (HBV). It acts as a chain terminator after incorporation into the growing viral DNA chain, thereby inhibiting viral replication.
Pregnancy: Pregnancy Category B. No evidence of risk in animal studies. Extensive data from pregnancy registries show no increased risk of major birth defects. Recommended as part of preferred ART regimens in pregnancy. The benefit of treatment outweighs potential risk.
Driving: Dizziness and fatigue have been reported. Patients should be cautioned about operating machinery or driving until they know how the medication affects them.
| Didanosine (ddI) | Increases ddI concentration; may increase ddI-associated adverse effects (pancreatitis, neuropathy). Should be administered separately. | Major |
| Adefovir dipivoxil | Additive nephrotoxicity; concurrent use not recommended. | Major |
| NSAIDs (e.g., Ibuprofen, Diclofenac) | May increase risk of nephrotoxicity. Monitor renal function closely. | Moderate |
| Aminoglycosides, Vancomycin | Increased risk of nephrotoxicity. Avoid concurrent use if possible. | Major |
| Probenecid | May increase tenofovir concentration by competing for renal tubular secretion. Monitor for adverse effects. | Moderate |
| Lopinavir/ritonavir | May increase tenofovir plasma levels. Monitor for renal effects. | Moderate |
| Hepatitis B antivirals (e.g., Entecavir) | No significant interaction, but used in combination for HBV may increase risk of resistance if not fully suppressive. | Minor |
Same composition (Tenofovir disoproxil fumarate (300mg)), different brands: