A fixed-dose combination (FDC) of two nucleoside reverse transcriptase inhibitors (NRTIs) used as first-line antiretroviral therapy (ART) for the treatment of Human Immunodeficiency Virus (HIV) infection. Lamivudine and Zidovudine work synergistically to inhibit viral replication, thereby reducing viral load, increasing CD4 cell counts, and slowing disease progression. This combination is a cornerstone of public health programs in India under the National AIDS Control Organization (NACO) guidelines.
Adult: One tablet (Lamivudine 150mg + Zidovudine 300mg) orally, twice daily.
Note: Can be taken with or without food. Swallow whole with water. Maintain a strict 12-hourly schedule to ensure consistent drug levels. If a dose is missed, take it as soon as remembered, but if it is almost time for the next dose, skip the missed dose. Do not double the dose.
Both are nucleoside analogues that require intracellular phosphorylation to their active triphosphate forms. These active metabolites competitively inhibit the HIV reverse transcriptase enzyme and act as chain terminators during viral DNA synthesis, thereby halting viral replication.
Pregnancy: Pregnancy Category C. However, it is recommended and widely used for treatment of HIV and PMTCT. The benefits of controlling maternal HIV and preventing transmission to the fetus outweigh the risks. Register with the Antiretroviral Pregnancy Registry. Dose adjustments are not routinely required.
Driving: Dizziness and fatigue have been reported. Patients should be cautioned about operating machinery or driving until they know how the medication affects them.
| Ganciclovir/Valganciclovir | Additive myelosuppression (severe neutropenia, anemia). | Major |
| Ribavirin | Antagonistic effect on Zidovudine's antiviral activity; may increase risk of lactic acidosis. | Major |
| Stavudine (d4T) | Pharmacological antagonism; concurrent use is contraindicated. | Major |
| Doxorubicin | May antagonize the anti-HIV effect of Zidovudine. | Moderate |
| Phenytoin | May alter phenytoin levels; Zidovudine levels may be increased. | Moderate |
| Probenecid | Inhibits glucuronidation of Zidovudine, increasing its toxicity risk. | Moderate |
| Trimethoprim-Sulfamethoxazole | Increases Lamivudine levels by ~40%. Usually safe but monitor for Lamivudine toxicity in renal impairment. | Moderate |
| Other Nephrotoxic drugs (e.g., Aminoglycosides, Amphotericin B) | May increase risk of renal impairment, affecting Lamivudine excretion. | Moderate |