Tivizid
300 mg+150 mg+300 mg
Square Pharmaceuticals Ltd.
Indications
This is used for the treatment of human immunodeficiency virus type 1 (HIV-1) infection in combination with other antiretrovirals or alone.
Pharmacology
Abacavir is an antiviral agent that is a carbocyclic synthetic nucleoside analogue. Intracellular enzymes convert abacavir to the active metabolite carbovir triphosphate, an analogue of deoxyguanosine-5′-triphosphate (dGTP). Carbovir triphosphate inhibits HIV-1 reverse transcriptase (RT) activity by both competing with the natural substrate dGTP and incorporating into viral DNA. Because the incorporated nucleotide lacks a 3′-OH group, which is required to form the 5′ to 3′ phosphodiester linkage required for DNA chain elongation, viral DNA growth is terminated.
Lamivudine is a synthetic nucleoside analogue that is intracellularly phosphorylated to its active 5′ triphosphate metabolite, lamivudine triphosphate (L TP). HIV reverse transcriptase and HBV polymerase incorporate this nucleoside analogue into viral DNA, resulting in DNA chain termination.
Zidovudine, a structural analog of thymidine, is a prodrug that must be phosphorylated before it can be converted to its active 5′-triphosphate metabolite, zidovudine triphosphate (ZDV-TP). After incorporation of the nucleotide analogue, it inhibits the activity of HIV-1 reverse transcriptase (RT) via DNA chain termination. It competes with the natural substrate dGTP and binds to viral DNA. It also has a minor inhibitory effect on cellular DNA polymerase a and y.
Dosage & Administration
Adults and pediatric patients weighing at least 40 kg should take the following dose: One tablet taken orally twice daily with or without food is the recommended dosage.
Because this is a fixed-dose tablet that cannot be dose adjusted, it is not recommended for:
- Pediatric patients weighing less than 40 kg
- Patients whose creatinine clearance is less than 50 mL/min
- Patients suffering from mild hepatic impairment.
Interaction
Abacavir: Oral methadone clearance increased in a trial of 11 HIV-1-infected subjects receiving methadone maintenance therapy with 600 mg twice daily (twice the currently recommended dose). The majority of patients will not require a methadone dose modification as a result of this change; however, an increased methadone dose may be required in a limited group of patients.
Lamivudine: When single doses of lamivudine and sorbitol were administered together, there was a sorbitol dose dependent reduction in lamivudine exposures. Avoid combining sorbitol-containing medications with lamivudine-containing medications whenever possible.
Zidovudine: Because an antagonistic relationship has been demonstrated in vitro, zidovudine should not be used concurrently with the following drugs: Nucleoside analogues, Stavudine, Doxorubicin, e.g., ribavirin
Contraindications
This is not recommended for patients:
Who have the HLA-B*5701 allele
With prior hypersensitivity reaction to abacavir, lamivudine, or zidovudine.
With moderate or severe hepatic impairment.
Side Effects
In clinical trials, the most commonly reported adverse reactions (incidence at least 10%) were nausea, headache, malaise and fatigue, and nausea and vomiting.
Pregnancy & Lactation
Pregnancy Type C. There have been no adequate and well-controlled studies in pregnant women with this preparation. Only if the potential benefits outweigh the risks should this medication be used during pregnancy. HIV-infected women should be advised not to breastfeed due to the risk of HIV transmission.
Precautions & Warnings
Abacavir, a component of this preparation, has caused serious and sometimes fatal hypersensitivity reactions. These hypersensitivity reactions have included multi-organ failure and anaphylaxis, and have typically occurred within the first 6 weeks of abacavir treatment (median time to onset was 9 days); however, abacavir hypersensitivity reactions have occurred at any time during treatment. Patients with the HLA B*5701 allele are more likely to develop abacavir hypersensitivity reactions; however, patients without the HLA-B*5701 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-B*5701 screening was not performed. When subjects carrying the HLA-B*5701 allele were excluded from clinical trials, the incidence of suspected abacavir hypersensitivity reactions was 1%. The clinical diagnosis of hypersensitivity reaction must remain the basis of clinical decision making in any patient treated with abacavir.
Overdose Effects
There is no specific treatment for this medication overdose. If an overdose occurs, the patient should be monitored and standard supportive treatment should be administered as needed.
Therapeutic Class
Drugs for HIV / Anti-retroviral drugs
Storage Conditions
Keep in a cool, dry place. Protect from light and moisture. Keep the medication out of children’s reach.