Sustiva

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 first-line highly active antiretroviral therapy (HAART) regimens, it works by binding directly to reverse transcriptase, blocking RNA- and DNA-dependent DNA polymerase activities. This action prevents the replication of the viral genome, thereby reducing viral load and increasing CD4 cell counts. Its once-daily dosing and high barrier to resistance—when used appropriately—make it a clinically validated option for treatment-naïve and certain treatment-experienced patients. Healthcare providers value its established efficacy profile and its role in long-term viral suppression strategies.

Features

• Active pharmaceutical ingredient: Efavirenz 600 mg
• Pharmacologic class: Non-nucleoside reverse transcriptase inhibitor (NNRTI)
• Standard dosage form: Film-coated tablet for oral administration
• Recommended dosing frequency: Once daily, preferably at bedtime
• FDA-approved for use in adults and pediatric patients ≥3 months old and weighing ≥3.5 kg
• Often combined with emtricitabine/tenofovir disoproxil fumarate as a fixed-dose regimen

Benefits

• Achieves and maintains viral suppression below detectable limits in compliant patients
• Contributes to immune reconstitution as evidenced by increased CD4+ T-cell counts
• Convenient once-daily dosing supports adherence and reduces pill burden
• Demonstrates high genetic barrier to resistance when used in combination therapy
• Suitable for a broad patient population, including pediatric cases ≥3 months
• Well-established long-term safety and efficacy data from clinical trials and post-marketing surveillance

Common use

Sustiva is primarily prescribed as part of combination antiretroviral therapy for the management of HIV-1 infection. It is commonly used in treatment-naïve adults and adolescents, as well as in certain virologically suppressed patients switching regimens. It is often co-administered with nucleoside reverse transcriptase inhibitors (NRTIs) such as emtricitabine and tenofovir. In pediatric HIV management, weight-based dosing allows for tailored treatment in children older than three months. Its use is guided by resistance testing where appropriate, and it remains a preferred agent in many local and international treatment guidelines due to its potency and dosing convenience.

Dosage and direction

The recommended oral dose for adults is 600 mg once daily. For pediatric patients, dosing is weight-based:

• 10 to <15 kg: 200 mg once daily
• 15 to <20 kg: 250 mg once daily
• 20 to <25 kg: 300 mg once daily
• 25 to <32.5 kg: 350 mg once daily
• 32.5 to <40 kg: 400 mg once daily
• ≥40 kg: 600 mg once daily

Administration should occur on an empty stomach, preferably at bedtime, to improve tolerability of central nervous system-related side effects during the initial treatment phase. Tablets must be swallowed whole and not crushed, chewed, or broken.

Precautions

Patients should be informed about potential neuropsychiatric symptoms, including dizziness, insomnia, abnormal dreams, impaired concentration, and depression. These are most common during the first weeks of therapy and often resolve with continued use. Severe psychiatric adverse reactions, including severe depression, suicidal ideation, and aggressive behavior, have been reported. Liver function should be monitored before and during treatment; discontinuation may be necessary in cases of severe hepatic impairment. Use with caution in patients with a history of seizures or psychiatric illness. Pregnancy should be avoided due to risk of neural tube defects; effective contraception is mandatory.

Contraindications

Sustiva is contraindicated in patients with known hypersensitivity to efavirenz or any component of the formulation. Coadministration with elbasvir/grazoprevir, voriconazole, cisapride, midazolam, triazolam, ergot derivatives, or St. John’s wort is contraindicated due to the potential for serious or life-threatening reactions. It is also contraindicated in patients with severe hepatic impairment.

Possible side effects

Common adverse reactions (≥10%) include:

• Rash (usually mild to moderate; resolves with continued therapy)
• Dizziness
• Insomnia
• Fatigue
• Abnormal dreams
• Nausea
• Headache

Serious side effects may include:

• Severe skin reactions (Stevens-Johnson syndrome, erythema multiforme)
• Hepatotoxicity
• Psychiatric symptoms (severe depression, suicidal thoughts)
• Convulsions
• Redistribution/accumulation of body fat (lipodystrophy)

Drug interaction

Efavirenz is a moderate CYP3A4 inducer and may alter concentrations of coadministered drugs. Significant interactions include:

• Reduced concentrations of: atazanavir, boceprevir, clarithromycin, itraconazole, ketoconazole, posaconazole, voriconazole, rifabutin, warfarin, and certain hormonal contraceptives
• Increased concentrations of: rifampin, voriconazole (contraindicated)
• Use with caution with other CNS depressants, including benzodiazepines

Consult full prescribing information before initiating new medications.

Missed dose

If a dose is missed, it should be taken as soon as possible, unless it is almost time for the next dose. In that case, the missed dose should be skipped and the regular dosing schedule resumed. Doubling doses is not recommended.

Overdose

There is no specific antidote for efavirenz overdose. Symptoms may include increased nervous system symptoms. 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 between 15–30°C (59–86°F). Keep in the original container and protect from moisture and light. Keep out of reach of children and pets.

Disclaimer

This information is intended for healthcare professionals and should not replace clinical judgment. Always consult the full prescribing information before initiating therapy. Dosage and administration must be individualized based on patient characteristics, viral resistance, and concomitant medications. Not all side effects or interactions are listed here.

Reviews

Sustiva has been extensively studied in clinical trials such as ACTG 5095 and STARTMRK, demonstrating durable virologic response and a generally acceptable safety profile. Many clinicians report high patient satisfaction due to its once-daily dosing, though some note the need for careful patient education regarding neuropsychiatric effects. Long-term real-world evidence supports its role in maintaining viral suppression, though lipid abnormalities and neuropsychiatric tolerability remain considerations in certain populations.