Combination Antiretroviral: This tablet contains a fixed-dose combination of two active ingredients: Zidovudine (A) 300 mg and Lamivudine (B) 150 mg.
Adult Dosage: This specific strength is a standard dosage formulated for adult patients, with one tablet typically taken twice daily.
NRTI Class: Both zidovudine and lamivudine are classified as Nucleoside Reverse Transcriptase Inhibitors (NRTIs), a foundational class of drugs for managing HIV.
Not Monotherapy: This combination is not a complete regimen on its own. It is always used as part of a multi-drug regimen with at least one other antiretroviral agent from a different class to provide a complete and effective treatment plan.
Advantages
Improved Adherence: The fixed-dose combination of two drugs into a single tablet significantly reduces the overall pill burden, making the regimen easier for patients to follow and thereby improving medication adherence.
Synergistic Antiviral Effect: Both zidovudine and lamivudine work synergistically to suppress HIV replication, providing a powerful and effective therapeutic combination.
Established Efficacy: The efficacy of this combination has been well-established through extensive clinical trials, and it is a cornerstone of global HIV treatment guidelines.
Reduced Resistance: The combination of two NRTIs makes it more difficult for the virus to develop resistance to both drugs simultaneously, enhancing the long-term effectiveness of the therapy.
Uses
HIV-1 Infection: Indicated for the treatment of HIV-1 infection in adults and adolescents weighing at least 30 kg, as part of a combination regimen.
First-Line Therapy: It is a common component of first-line antiretroviral therapy (ART) regimens for adults, often combined with a third agent from a different class.
Post-Exposure Prophylaxis (PEP): This combination is a key component of regimens used for PEP to prevent HIV infection after a potential occupational or non-occupational exposure.
Pregnancy: It is a widely used combination for managing HIV in pregnant patients to reduce the risk of perinatal transmission.
Nature
Nucleoside Reverse Transcriptase Inhibitors (NRTIs): Both zidovudine and lamivudine are NRTI prodrugs that are converted to their active triphosphate forms inside the cell.
Mechanism of Action: Their active forms compete with natural nucleosides to be incorporated into the growing viral DNA chain. This leads to premature chain termination, which blocks the action of the viral enzyme reverse transcriptase.
Inhibition of Viral Replication: By inhibiting reverse transcriptase, both drugs prevent the transcription of the HIV RNA genome into DNA, thus blocking a crucial step in the viral replication cycle.
Side Effects: Zidovudine is known to cause bone marrow suppression, which can lead to anemia and neutropenia. This requires careful hematological monitoring, particularly during the initial months of therapy.
Storage
Temperature: Store the tablets at controlled room temperature, typically between 20∘C to 25∘C (68∘F to 77∘F).
Protection: Keep the tablets in their original, tightly closed container, protected from light and moisture.
Patient Compliance: Patients must be educated on the importance of taking every dose as prescribed to prevent the development of viral resistance and to ensure long-term treatment success.
Child Safety: Store the medication in a secure location, out of the reach of children and pets.
