A fixed-dose combination (FDC) tablet of three antiretroviral agents for the treatment of Human Immunodeficiency Virus type 1 (HIV-1) infection. It is a complete once-daily regimen containing two nucleoside reverse transcriptase inhibitors (NRTIs) - Emtricitabine and Tenofovir disoproxil fumarate (TDF) - and one non-nucleoside reverse transcriptase inhibitor (NNRTI) - Efavirenz. It is a cornerstone of first-line antiretroviral therapy (ART) in India as per the National AIDS Control Organization (NACO) guidelines, offering high efficacy, convenience, and a well-established safety profile.
Adult: One tablet (containing Emtricitabine 200mg + Tenofovir disoproxil fumarate 300mg + Efavirenz 600mg) orally once daily, preferably on an empty stomach at bedtime to improve tolerability of CNS side effects from Efavirenz.
Note: Take on an empty stomach, preferably at bedtime. Swallow whole with water. Taking with a high-fat meal increases Efavirenz absorption and may increase CNS side effects. For improved tolerability, initiating at bedtime for the first 2-4 weeks is recommended. If dose is missed within 12 hours of the usual time, take it immediately. If >12 hours have passed, skip the missed dose and take the next dose at the regular time. Do not double the dose.
This combination inhibits the reverse transcriptase enzyme of HIV-1 via two distinct mechanisms, preventing the conversion of viral RNA into DNA and thus blocking viral replication.
Pregnancy: Pregnancy Category D (as per US FDA). Efavirenz is contraindicated in the first trimester due to risk of neural tube defects. For women of childbearing potential, a pregnancy test should be performed before initiation and reliable contraception must be used. If pregnancy is confirmed in the first trimester, switch to an alternative regimen. Use in second/third trimester may be considered if benefits outweigh risks, but alternatives (e.g., Dolutegravir-based regimens) are preferred as per current WHO and NACO guidelines.
Driving: Efavirenz can cause dizziness, impaired concentration, and somnolence, especially during the first weeks of therapy. Patients should be cautioned about driving or operating machinery until they know how the medication affects them.
| Rifampicin | Decreases Efavirenz plasma levels; may require Efavirenz dose increase to 800mg (not possible with this FDC). Consider alternative ART. | Major |
| Voriconazole | Efavirenz decreases Voriconazole levels; Voriconazole increases Efavirenz levels. Coadministration is contraindicated. | Major |
| Clarithromycin | Efavirenz decreases Clarithromycin levels; Azithromycin is preferred. | Moderate |
| Warfarin | Efavirenz may affect levels; monitor INR closely. | Moderate |
| Anticonvulsants (Carbamazepine, Phenytoin, Phenobarbital) | May decrease Efavirenz levels; therapeutic drug monitoring advised. | Moderate |
| Azole Antifungals (Ketoconazole, Itraconazole) | Efavirenz decreases azole levels; monitor efficacy. | Moderate |
| Atorvastatin | Efavirenz decreases atorvastatin levels; may need dose adjustment. | Moderate |
| Methadone | Efavirenz decreases methadone levels; may precipitate opioid withdrawal; methadone dose may need increase. | Moderate |
| Acyclovir, Valacyclovir, Cidofovir, Aminoglycosides, NSAIDs | Increased risk of nephrotoxicity with Tenofovir. | Moderate |
| Other CYP3A4 inducers/inhibitors | Complex interactions; consult detailed resources. | Variable |