Sustiva (efavirenz) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) indicated for the treatment of human immunodeficiency virus type 1 (HIV-1) infection in combination with other antiretroviral agents. As a cornerstone of many highly active antiretroviral therapy (HAART) regimens, it offers potent viral suppression, contributing to improved immunologic function and long-term disease control. Its once-daily dosing supports adherence, a critical factor in treatment success, while its well-characterized safety profile makes it a trusted option for clinicians managing HIV-1 in diverse patient populations.

Features

• Active ingredient: Efavirenz 600 mg
• Pharmacologic class: Non-nucleoside reverse transcriptase inhibitor (NNRTI)
• Formulation: Film-coated tablets for oral administration
• Dosing frequency: Once daily, preferably at bedtime
• FDA-approved for use in combination therapy for HIV-1 infection
• Bioavailability: Approximately 40–45% under fasting conditions
• Half-life: 40–55 hours, allowing consistent therapeutic coverage

Benefits

• Achieves and maintains viral load suppression below detectable limits
• Helps increase CD4+ T-cell counts, restoring immune function
• Reduces risk of HIV-related complications and disease progression
• Once-daily dosing supports long-term adherence to therapy
• Proven efficacy in treatment-naïve and certain treatment-experienced patients
• Available in fixed-dose combinations for simplified regimens

Common use

Sustiva is used as part of combination antiretroviral therapy for the treatment of HIV-1 infection in adults and pediatric patients aged 3 months and older weighing at least 3.5 kg. It is commonly prescribed in initial treatment regimens due to its potency, durability, and convenience. It may also be used in certain switch strategies for virologically suppressed patients seeking regimen simplification. It is always used in conjunction with other antiretroviral agents to prevent the emergence of resistance.

Dosage and direction

The recommended adult dose is 600 mg orally once daily. For pediatric patients, dosing is based on body weight. Administration should occur on an empty stomach, preferably at bedtime, to improve tolerability of central nervous system-related side effects, especially during the initial weeks of therapy. Tablets should be swallowed whole with water. Dosage adjustment is required when coadministered with certain drugs such as rifampin or voriconazole. Do not crush, break, or chew tablets.

Precautions

Sustiva has been associated with serious psychiatric symptoms including severe depression, suicidal ideation, and aggressive behavior. Patients with a history of psychiatric illness should be monitored closely. It may cause dizziness, impaired concentration, and somnolence; patients should avoid hazardous activities until they know how the drug affects them. Rash is common, usually mild to moderate, but severe skin reactions, including Stevens-Johnson syndrome, have been reported. Liver enzyme elevations and hepatitis may occur. Use with caution in patients with hepatic impairment. It may increase lipid levels; monitor serum triglycerides and cholesterol.

Contraindications

Sustiva is contraindicated in patients with known hypersensitivity to efavirenz or any component of the formulation. Coadministration with elbasvir/grazoprevir is contraindicated due to the potential loss of virologic response and possible resistance. It is also contraindicated with certain drugs that are highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events (e.g., cisapride, midazolam, triazolam, ergot derivatives, St. John’s wort).

Possible side effects

Common side effects (≥10%) include: dizziness, insomnia, somnolence, abnormal dreams, nausea, fatigue, rash. Less common but serious side effects may include: severe psychiatric symptoms (depression, suicidal thoughts), severe skin reactions, hepatotoxicity, convulsions, and lipodystrophy. Immune reconstitution syndrome has been reported in patients treated with combination antiretroviral therapy.

Drug interaction

Efavirenz is a moderate inducer of CYP3A4 and an inhibitor of CYP2C9/2C19. It may decrease concentrations of drugs metabolized by these enzymes (e.g., methadone, voriconazole, clarithromycin, itraconazole, rifabutin, warfarin, certain anticonvulsants and antidepressants). Conversely, drugs that induce CYP3A4 (e.g., rifampin) may decrease efavirenz concentrations. Coadministration with other NNRTIs is not recommended. Consult full prescribing information for a comprehensive list and dosage adjustments.

Missed dose

If a dose is missed, take it as soon as it is remembered, unless it is almost time for the next dose. Do not double the next dose. Maintaining regular dosing is important to avoid subtherapeutic levels and potential resistance.

Overdose

There is limited experience with overdose. Symptoms may include increased nervous system symptoms (dizziness, confusion, agitation). There is no specific antidote. Treatment should consist of general supportive measures, including monitoring of vital signs and observation of clinical status. Since efavirenz is highly protein-bound, dialysis is unlikely to remove significant quantities.

Storage

Store at 25°C (77°F); excursions permitted to 15–30°C (59–86°F). Keep in the original container, tightly closed, and protect from moisture and light. Keep out of reach of children and pets.

Disclaimer

This information is intended for educational purposes and does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with any questions regarding a medical condition or before starting any new treatment. Do not disregard professional medical advice or delay seeking it based on information provided here.

Reviews

Sustiva has been extensively studied in clinical trials and real-world settings, demonstrating durable virologic suppression and a generally manageable side effect profile. Many clinicians value its once-daily dosing and high barrier to resistance within the NNRTI class. Patient experiences vary; some report significant neuropsychiatric effects or vivid dreams, which often diminish over time, while others tolerate it well long-term. It remains a foundational option in many guidelines for initial HIV therapy.