COMBIVIR
General description

Combivir is the brand name for a combination drug produced by Glaxo Wellcome Inc. It contains both Zidovudine and lamivudine. These two drugs can be used in combination to fight HIV disease.

Mechanism

Both lamivudine and zidvudine are phosphorylated in the body and inhibit reverse transcription by the HIV RNA. The primary mode of action for both lamivudine and zidovudine is termination of the DNA chain after incorporation into the viral genome. It is found that resistance to lamivudine typically develops in patients within 12 weeks, but combination treatment of the two drugs toeghter delays resistance to zidovudine, making overall treatment more effective.

Indications

Combivir is indicated for treatment of HIV infection.

Usage/Dosage

Recommended dosage for adults and adolescents at least 12 years of age is one tablet (150 mg lamivudine, 300 mg zidovudine) twice daily. Patients requiring reduced dosage should not receive Combivir.

Precautions

Combivir is a fixed-dosage drug, and as such, those patients who require reduced dosage for treatment should not receive Combivir. This includes patients with low body weight (less than 50 kg or 110 lbs) as well as patients with renal and liver dysfunction Patients should be informed that Combivir is not a cure for HIV- transmission is still possible during treatment, as is the progression of HIV disease itself. Combination treatment with ganciclovir, interpheron-alpha,bone marrow suppressives, and cytotoxic agents can increase change of hemotoxicity of Combivir.

Contraindications

Combivir is contraindicated for any patients with known allergies to any components of the drug. Patients with low body weight and severe liver and kidney dysfunction should not reveive Combivir. Warnings for other drugs should also be consulted before beginning any combination treatment program. Patients with bone marrow compromise have higher rates of anemia and neutropenia, so caution should be exercised.

Potential Adverse Effects

The most common effects are headache, anesthenia, malaise, nausea, diarrhea, nasal signs and symptoms, and cough. Lactic acidosis, pancreatitis, vasculitis, and sensitization reactions are all severe effects that have been reported, however. Adverse reactions tend to worsen as HIV disease progresses, so patients should be monitored.