Tivizid

Recommended dosage for adults and pediatric patients weighing at least 40 kg: The recommended dosage is one tablet taken orally twice daily with or without food. Due to fixed-dose tablet and cannot be dose adjusted, this is not recommended for: Pediatric patients who weigh less than 40 kg. Patients with creatinine clearance less than 50 ml/minute Patients with mild hepatic impairment.

Abacavir is a carbocyclic synthetic nucleoside analogue and an antiviral agent. Intracellularly, abacavir is converted by cellular enzymes to the active metabolite carbovir triphosphate, an analogue of deoxyguanosine-5'-triphosphate (dGTP). Carbovir triphosphate inhibits the activity of HIV-1 reverse transcriptase (RT) both by competing with the natural substrate dGTP and by its incorporation into viral DNA. Viral DNA growth is terminated because the incorporated nucleotide lacks a 3'-OH group, which is needed to form the 5′ to 3′ phosphodiester linkage essential for DNA chain elongation. Lamivudine is a synthetic nucleoside analogue and is phosphorylated intracellularly to its active 5'-triphosphate metabolite, lamivudine triphosphate (L-TP). This nucleoside analogue is incorporated into viral DNA by HIV reverse transcriptase and HBV polymerase, resulting in DNA chain termination. Zidovudine, a structural analog of thymidine, is a prodrug that must be phosphorylated to its active 5′-triphosphate metabolite, zidovudine triphosphate (ZDV-TP). It inhibits the activity of HIV-1 reverse transcriptase (RT) via DNA chain termination after incorporation of the nucleotide analogue. It competes with the natural substrate dGTP and incorporates itself into viral DNA. It is also a weak inhibitor of cellular DNA polymerase α and γ.

The most commonly reported adverse reactions (incidence at least 10%) in clinical trials were nausea, headache, malaise and fatigue, and nausea and vomiting.

This is contraindicated in patients: Who have the HLA-B*5701 allele With prior hypersensitivity reaction to abacavir, lamivudine, or zidovudine. With moderate or severe hepatic impairment.

Serious and sometimes fatal hypersensitivity reactions have occurred with abacavir, a component of this preparation. These hypersensitivity reactions have included multi-organ failure and anaphylaxis and typically occurred within the first 6 weeks of treatment with abacavir (median time to onset was 9 days); although abacavir hypersensitivity reactions have occurred any time during. Patients who carry the HLA-B5701 allele are at a higher risk of abacavir hypersensitivity reactions; although, patients who do not carry the HLA-B5701 allele have developed hypersensitivity reactions. Hypersensitivity to abacavir was reported in approximately 206 (8%) of 2,670 patients in 9 clinical trials with abacavir-containing products where HLA-B5701 screening was not performed. The incidence of suspected abacavir hypersensitivity reactions in clinical trials was 1% when subjects carrying the HLA-B5701 allele were excluded. In any patient treated with abacavir, the clinical diagnosis of hypersensitivity reaction must remain the basis of clinical decision making.

Abacavir: In a trial of 11 HIV-1-infected subjects receiving methadone-maintenance therapy with 600 mg twice daily (twice the currently recommended dose), oral methadone clearance increased. This alteration will not result in a methadone dose modification in the majority of patients; however, an increased methadone dose may be required in a small number of patients. Lamivudine: Coadministration of single doses of lamivudine and sorbitol resulted in a sorbitol dose-dependent reduction in lamivudine exposures. When possible, avoid use of sorbitol-containing medicines with lamivudine-containing medicines Zidovudine: Concomitant use of zidovudine with the following drugs should be avoided since an antagonistic relationship has been demonstrated in vitro: Stavudine, Doxorubicin, Nucleoside analogues, e.g., ribavirin