Triovix150 mg+300 mg+200 mg

Triovix is a fixed-dose combination (FDC) antiretroviral tablet combining two nucleoside reverse transcriptase inhibitors (NRTIs) with one non-nucleoside reverse transcriptase inhibitor (NNRTI) in a single tablet, intended to simplify triple-drug antiretroviral therapy (ART).

Established / Guideline-Supported Use

• Treatment of HIV-1 infection: Triovix is indicated as a complete triple-drug antiretroviral regimen for the treatment of HIV-1 infection in treatment-naive adults and adolescents, used in accordance with WHO and national HIV treatment guidelines, particularly as a first-line regimen in resource-limited settings.
• Pediatric use: corresponding pediatric-strength formulations of the same three-drug combination are used for treatment of HIV-1 infection in children, dosed by body weight per national/WHO pediatric ART guidelines (see Use in Special Populations).

Important Notes

• Triovix must always be used as part of a complete, guideline-directed regimen and must never be used as monotherapy with only one component.
• Triovix is not recommended for HIV post-exposure prophylaxis (PEP) in HIV-negative individuals because of the risk of severe nevirapine-associated hepatotoxicity and skin reactions in this setting.
• Choice of regimen, including whether Triovix remains appropriate, should be individualized by a physician based on current national/WHO first-line ART recommendations, prior treatment history, and (where available) resistance testing.

Lamivudine + Zidovudine + Nevirapine is available as a fixed-dose combination tablet. A common adult-strength tablet contains:

• Lamivudine 150 mg
• Zidovudine 300 mg
• Nevirapine 200 mg

Lower-strength scored or dispersible tablets of the same three-drug combination, formulated for weight-based pediatric dosing, are also manufactured. Exact strengths and available dosage forms of Lamivudine + Zidovudine + Nevirapine may vary by manufacturer; always check the product label/pack insert of the specific brand dispensed.

Triovix combines three antiretroviral medicines used together as first-line combination antiretroviral therapy (ART) for HIV-1 infection: lamivudine and zidovudine, both nucleoside reverse transcriptase inhibitors (NRTIs), and nevirapine, a non-nucleoside reverse transcriptase inhibitor (NNRTI). Combining all three drugs into a single tablet reduces daily pill burden and helps support treatment adherence, which is essential to keep the virus suppressed and to prevent development of drug resistance.

Triovix does not cure HIV infection but, when taken consistently as prescribed, suppresses viral replication, preserves immune function, and reduces the risk of HIV-related illness and transmission.

Triovix belongs to the class of combination antiretroviral therapy (ART) for HIV-1 infection, comprising:

• Lamivudine – Nucleoside Reverse Transcriptase Inhibitor (NRTI)
• Zidovudine – Nucleoside Reverse Transcriptase Inhibitor (NRTI)
• Nevirapine – Non-Nucleoside Reverse Transcriptase Inhibitor (NNRTI)

Mechanism

Lamivudine + Zidovudine + Nevirapine works through two complementary mechanisms that both inhibit the HIV reverse transcriptase enzyme, which the virus needs to convert its RNA into DNA. Lamivudine and zidovudine are NRTIs that are phosphorylated inside cells to their active triphosphate forms; these compete with the natural nucleotides for incorporation into the growing viral DNA chain and cause chain termination once incorporated. Nevirapine, an NNRTI, binds directly to a separate site on reverse transcriptase and blocks its polymerase activity non-competitively, without requiring intracellular activation.

Pharmacokinetics

Because nevirapine induces its own clearance, dosing of Lamivudine + Zidovudine + Nevirapine is typically preceded by a nevirapine lead-in period at a lower dose (see Dosage and Administration) to reduce the risk of dose-related rash.

Triovix tablets may be taken with or without food. Swallow the tablet whole with a glass of water; do not crush or chew unless the specific product is designed to be dispersed in water. Take doses at evenly spaced intervals (approximately every 12 hours) at the same times each day to maintain consistent drug levels. Do not stop, skip, alter, or share doses of Triovix without medical advice, as inconsistent dosing risks loss of viral suppression and development of drug resistance.

Triovix has several clinically significant drug interactions, mainly related to nevirapine's effect on the CYP3A4/CYP2B6 enzyme system:

• Rifampicin: significantly reduces nevirapine plasma concentrations through enzyme induction, risking loss of virologic control; co-administration is generally avoided and an alternative regimen is preferred when rifampicin-containing anti-tuberculosis therapy is required.
• Ketoconazole and other azole antifungals: nevirapine reduces ketoconazole concentrations substantially; concurrent use is not recommended.
• Hormonal contraceptives: nevirapine can reduce the effectiveness of hormonal contraceptives; an additional or alternative non-hormonal contraceptive method is recommended.
• Methadone: nevirapine can lower methadone levels and precipitate opioid withdrawal; dose adjustment and monitoring are required.
• Other bone-marrow suppressive drugs (e.g., ganciclovir, cytotoxic chemotherapy, ribavirin): co-administration with zidovudine increases the risk of anemia/neutropenia; avoid where possible and monitor blood counts closely if unavoidable.
• Stavudine: must not be combined with zidovudine (a component of Triovix) because the two NRTIs antagonize each other's intracellular activation.
• Other drugs highly dependent on CYP3A for clearance: nevirapine, as a CYP3A inducer, can meaningfully raise or lower levels of such drugs; concomitant use requires case-by-case physician review (see Contraindications).

Side effects of Triovix reflect the combined profile of its three components.

Patients should seek prompt medical attention for new rash, yellowing of the skin/eyes, unusual tiredness, easy bruising/bleeding, or signs of severe allergic reaction.

Pregnancy: Triovix should be used in pregnancy only in line with current national/WHO guideline-directed antiretroviral regimens for pregnant women living with HIV, individualized by a physician, taking into account nevirapine-specific considerations. Use should occur only if a physician judges the benefit of maintaining viral suppression and reducing mother-to-child transmission justifies the potential risks; pregnant women taking Triovix should remain under close specialist supervision and never start, stop, or change this medicine without medical advice.

Breastfeeding: Decisions about breastfeeding while taking Triovix should follow current national/WHO infant-feeding guidance for mothers living with HIV and should be individualized with a physician, since all three components pass into breast milk.

Serious Skin Reactions

Triovix carries a boxed-warning-level risk (from its nevirapine component) of severe, life-threatening skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis, with the highest risk in the first several weeks of treatment. Patients must stop Triovix and seek immediate medical attention for any new or worsening rash, especially if accompanied by fever, blistering, mouth sores, or swelling.

Hepatotoxicity

Severe, potentially fatal liver toxicity has been reported with the nevirapine component, with greatest risk during the first 18 weeks of therapy. Liver function should be monitored closely, particularly during this period, and Triovix should be stopped immediately if signs of hepatitis or hypersensitivity develop.

Hematologic Toxicity

Zidovudine can cause bone marrow suppression, including anemia and neutropenia; regular complete blood count monitoring is recommended, especially in patients with advanced HIV disease or low baseline blood counts.

Lactic Acidosis / Hepatomegaly with Steatosis

Nucleoside analogues, including the lamivudine and zidovudine components of Triovix, have been associated with lactic acidosis and severe hepatomegaly with steatosis, sometimes fatal; treatment should be suspended if clinical or laboratory findings suggestive of this occur.

Not for Post-Exposure Prophylaxis

Triovix should not be used for HIV post-exposure prophylaxis in HIV-negative individuals because of the disproportionate risk of severe nevirapine-related hepatotoxicity and skin reactions in that setting.

Immune Reconstitution and Resistance

Immune reconstitution inflammatory syndrome may occur after starting therapy. Strict, uninterrupted adherence to Triovix is essential: take exactly as prescribed by your physician; do not stop, extend, skip doses, alter the schedule, or share this medicine with others without medical advice, since inconsistent use rapidly promotes HIV drug resistance and treatment failure. Do not stop Triovix abruptly without physician guidance, as nevirapine's long half-life can leave a period of unprotected NRTI-only exposure that raises the risk of NNRTI resistance; your physician may direct a specific stopping strategy.

There is no specific antidote for Triovix overdose. Reported effects with individual components have included nausea, vomiting, headache, and, at very high exposure, hematologic or hepatic abnormalities. Anyone who has taken more than the prescribed dose of Triovix should seek immediate medical attention or contact a poison control center/emergency services rather than attempting home treatment; management is supportive, guided by symptoms and clinical monitoring.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

• Renal impairment: the fixed-dose Triovix tablet is generally unsuitable for patients with significant renal impairment because its NRTI components require dose reduction that cannot be made within a combined tablet; separately dosed components are preferred (see Dosage and Administration).
• Hepatic impairment: contraindicated in moderate-to-severe hepatic impairment; use with caution and close monitoring in mild impairment (see Contraindications).
• Elderly: limited specific data; use with routine monitoring for renal, hepatic, and hematologic function given the higher likelihood of comorbidities and concomitant medications in this group.
• Children: treated using weight-based dosing with pediatric-strength formulations, not the adult tablet (see Pediatric Use).

Triovix, like all antiretroviral therapy, is generally intended for long-term, typically lifelong, use once started, to maintain continuous viral suppression. Treatment duration and any changes to the regimen (including switching away from Triovix) should be decided only by the treating physician, based on virologic response, tolerability, and evolving national/WHO treatment guidelines. Doses must not be skipped, and the regimen must not be stopped or altered without medical advice, as interruptions risk viral rebound and resistance.

Combination Antiretroviral Therapy (ART): Nucleoside Reverse Transcriptase Inhibitors (NRTIs) – Lamivudine, Zidovudine; Non-Nucleoside Reverse Transcriptase Inhibitor (NNRTI) – Nevirapine

Lamivudine + Zidovudine + Nevirapine suppresses HIV-1 replication through two complementary, non-overlapping mechanisms targeting the same viral enzyme, reverse transcriptase. Lamivudine and zidovudine, once phosphorylated intracellularly to their active triphosphate forms, act as competitive substrates that are incorporated into viral DNA by reverse transcriptase and cause premature chain termination. Nevirapine binds non-competitively to a hydrophobic pocket on reverse transcriptase distinct from the active site, inducing a conformational change that directly inhibits the enzyme's RNA- and DNA-dependent DNA polymerase activity. Using both mechanisms together as a triple-drug regimen suppresses viral replication more completely and raises the genetic barrier to resistance compared with either mechanism alone.

Triovix is used to treat HIV-1 infection in children using pediatric-strength scored or dispersible tablet formulations of the same three-drug combination, dosed strictly by body weight band according to current WHO/national pediatric ART dosing guidance; the adult-strength tablet is not appropriate for pediatric dosing and must not be split or estimated. A nevirapine dose lead-in period is also typically used in children who are not already established on the drug, to reduce rash risk, mirroring the adult approach. Safety and efficacy of specific pediatric strength combinations below defined age/weight thresholds should be confirmed against the specific product's approved labeling; where a particular age or weight group is not covered by that labeling, safety and efficacy have not been established and an alternative regimen should be used. Close monitoring of growth, liver function, and blood counts is recommended in children on Triovix, and strict adherence should be reinforced with caregivers.