A fixed-dose combination (FDC) of two nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) used primarily for the treatment of HIV-1 infection and for pre-exposure prophylaxis (PrEP) against HIV. Emtricitabine is a cytosine analogue, and tenofovir disoproxil fumarate (TDF) is an acyclic nucleoside phosphonate diester analogue of adenosine monophosphate. This combination is a cornerstone of first-line antiretroviral therapy (ART) in India and globally, known for its high efficacy, tolerability, and once-daily dosing.
Adult: One tablet (containing Emtricitabine 200mg + Tenofovir disoproxil fumarate 300mg) orally, once daily, with or without food.
Note: Swallow the tablet whole with water. Can be taken with or without food, but a high-fat meal increases tenofovir absorption. For PrEP, adherence is critical for effectiveness. Must be taken daily, not just before/after sexual activity.
The combination inhibits the reverse transcriptase enzyme of HIV-1, a critical enzyme for viral replication. Emtricitabine and tenofovir are both analogues of natural nucleosides/nucleotides. They are phosphorylated intracellularly by cellular kinases to their active diphosphate (Emtricitabine 5'-triphosphate, FTC-TP) and diphosphate (Tenofovir diphosphate, TFV-DP) forms, respectively. These active metabolites compete with the natural substrates (deoxycytidine 5'-triphosphate for FTC-TP and deoxyadenosine 5'-triphosphate for TFV-DP) for incorporation into the growing viral DNA chain by HIV-1 reverse transcriptase. Once incorporated, they act as chain terminators because they lack the 3'-hydroxyl group needed to form the next phosphodiester bond, thereby halting viral DNA synthesis and replication.
Pregnancy: Pregnancy Category B. No adequate and well-controlled studies in pregnant women. Emtricitabine and tenofovir cross the placenta. The combination is recommended for use in pregnant individuals living with HIV as part of a complete ART regimen to prevent mother-to-child transmission. The Antiretroviral Pregnancy Registry monitors outcomes. Benefits generally outweigh risks.
Driving: Dizziness and fatigue have been reported. Patients should be cautioned about operating machinery or driving if they experience these effects.
| Didanosine (ddI) | Increased didanosine concentrations and potential for didanosine-related adverse effects (pancreatitis, neuropathy). Tenofovir may increase ddI levels. | Major |
| Adefovir dipivoxil | Additive nephrotoxicity potential. | Major |
| Other nephrotoxic drugs (e.g., Aminoglycosides, Amphotericin B, Foscarnet, Ganciclovir, Vancomycin, NSAIDs like Ibuprofen) | Increased risk of renal impairment. | Major |
| Probenecid, Cidofovir | May increase tenofovir concentrations by competing for renal tubular secretion. | Moderate |
| Ledipasvir/Sofosbuvir or other HCV regimens containing Velpatasvir | May increase tenofovir exposure; monitor for tenofovir-associated adverse effects, especially renal. | Moderate |
| Rifampin, Rifabutin | May decrease tenofovir concentrations slightly; not considered clinically significant for efficacy. | Minor |
| Atazanavir (boosted with Ritonavir) | Increases tenofovir exposure. Monitor for renal toxicity. | Moderate |
Same composition (Emtricitabine (200mg) + Tenofovir disoproxil fumarate (300mg)), different brands: