Efavirenz Medications

Efavirenz is an antiretroviral medication used as part of combination therapy to treat HIV-1 infection.

Sustiva

Efavirenz

$3.87 per pill

200 | 600mg

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Efavirenz Information

Efavirenz is a cornerstone of modern antiretroviral therapy, belonging to the non-nucleoside reverse transcriptase inhibitor (NNRTI) class. By binding directly to HIV-1 reverse transcriptase, it halts the conversion of viral RNA into DNA, a critical step in the virus’s replication cycle. Approved worldwide for the treatment of HIV-1 infection in adults, efavirenz is available both as a standalone tablet (brand names such as Sustiva and Stocrin) and as part of fixed-dose combinations like Atripla. While its primary indication is for inclusion in three-drug regimens, clinicians sometimes employ efavirenz off-label for specific prevention strategies in mother-to-child transmission when other options are unsuitable. The drug’s long half-life supports once-daily dosing, and its central nervous system effects, including vivid dreams and dizziness, are well documented. Through our online pharmacy, patients in Singapore can obtain efavirenz in generic form at reduced cost, while still receiving the safety and quality assurances required by the Health Sciences Authority.

What is Efavirenz?

Efavirenz is classified as a non-nucleoside reverse transcriptase inhibitor (NNRTI), a drug class that interferes with the HIV-1 reverse transcriptase enzyme without mimicking the natural nucleosides. The U.S. Food and Drug Administration (FDA) granted initial approval in 1998, followed by the European Medicines Agency (EMA) and the World Health Organization (WHO) for use in combination antiretroviral therapy. In Singapore, the Health Sciences Authority (HSA) recognizes efavirenz as an approved component of HIV treatment regimens. The molecule binds to a hydrophobic pocket of reverse transcriptase, inducing a conformational change that prevents the enzyme from transcribing viral RNA. Efavirenz is marketed under several brand names-including Sustiva, Stocrin, and the combination product Atripla-and is widely available in generic form through our pharmacy service.

How Efavirenz Works

Mechanism of Action

Efavirenz attaches non-competitively to the reverse transcriptase enzyme’s NNRTI-binding site. This binding distorts the enzyme’s active configuration, rendering it unable to synthesize viral DNA from RNA. Because the drug does not compete with natural nucleotides, resistance emerges mainly through specific point mutations in the reverse transcriptase gene.

Therapeutic Effects

The inhibition of reverse transcriptase blocks a vital replication step, leading to a rapid decline in plasma HIV-1 RNA levels. When combined with two nucleos(t)ide reverse transcriptase inhibitors (NRTIs), efavirenz helps achieve and maintain viral suppression, improves CD4⁺ cell counts, and reduces the risk of opportunistic infections.

Onset and Duration

Steady-state plasma concentrations are typically reached after five to seven days of once-daily dosing, reflecting its long elimination half-life of 40-55 hours. Clinical viral load reductions are observable within two weeks, and maximal virologic benefit is usually attained by week eight of therapy.

Approved Uses and Applications

Approved Indications

HIV-1 infection in adults: Part of first-line triple therapy with two NRTIs, as recommended by the National HIV Treatment Guidelines of Singapore and endorsed by the HSA.
Fixed-dose combinations: Available in Atripla (efavirenz/tenofovir/emtricitabine) for simplification of regimen adherence.

Off-Label Uses

Efavirenz is occasionally employed off-label for pre-exposure prophylaxis (PrEP) in patients who cannot tolerate tenofovir-based options, though such use lacks formal regulatory endorsement. Clinicians also report limited off-label use in prevention of mother-to-child transmission when alternative NNRTIs are contraindicated, acknowledging the teratogenic risk profile.

Clinical Efficacy

Large phase III trials, such as the ACTG 5202 study published in The New England Journal of Medicine, demonstrated that efavirenz-based regimens achieved a 75 % rate of viral suppression (<50 copies/mL) at 48 weeks, comparable to protease-inhibitor-based arms. Meta-analyses in The Lancet HIV confirm sustained efficacy with once-daily dosing and highlight lower rates of treatment discontinuation due to adverse events when efavirenz is combined with tenofovir/emtricitabine.

Buying Efavirenz from Our Online Pharmacy

Why Choose Our Service

Accessing efavirenz in Singapore can be challenging due to limited stock in some local pharmacies. Our online pharmacy bridges that gap, offering a discreet, reliable channel that complies with HSA regulations and international quality standards.

Brand Names and Generic Options

Sustiva - patented formulation, often priced higher.
Stocrin - another branded option with comparable bioavailability.
Atripla - fixed-dose combination for once-daily simplicity.
Generic efavirenz - manufactured by WHO-prequalified suppliers, providing up to 40 % cost savings.

Quality & Safety

Through our platform, we partner with licensed international pharmacies that source medications from manufacturers audited to Good Manufacturing Practice (GMP) standards. All batches undergo third-party verification for potency and purity.

Pricing & Access

Generic tablets are typically priced at SGD 5-8 per 600 mg unit, while branded versions range from SGD 12-18. Returning customers enjoy a lifetime 10 % discount on all reorders, making long-term therapy more affordable.

Discreet Delivery

Orders ship via express courier in approximately 7 days or by standard mail within 3 weeks. Packages are sealed in unmarked, tamper-evident envelopes to protect your privacy.

Dosing, Formulations & Administration

Available Formulations

Efavirenz is supplied as 200 mg and 600 mg film-coated tablets. Fixed-dose combos (e.g., Atripla) contain a 600 mg efavirenz component. No liquid or injectable forms are marketed for adult use.

Typical Dosing Ranges

For most adults initiating therapy, clinicians start with 600 mg once daily, taken on an empty stomach to maximize absorption. Some treatment guidelines allow dose reduction to 400 mg when co-administered with potent CYP2B6 inhibitors, but such adjustments require professional oversight.

Administration Guidelines

Efavirenz should be taken at bedtime, preferably 20-30 minutes before sleep, to mitigate daytime dizziness and vivid dreams. Food can reduce oral bioavailability by up to 25 %; therefore, a fasted state is recommended. Swallow tablets whole; do not crush or chew.

Exact dosing must be individualized by a qualified healthcare provider based on viral load, liver function, and potential drug interactions.

Safety Profile & Considerations

Common Side Effects

Dizziness - reported in ~30 % of patients.
Vivid dreams or insomnia - experienced by up to 20 % of users.
Headache - occurs in ~15 % of individuals.
Nausea - noted in ~12 % of trial participants.
Rash - mild cutaneous eruptions appear in ~10 % of cases.

Serious Adverse Events

Hepatotoxicity - severe liver enzyme elevations have been documented; monitoring is advised, especially in patients with pre-existing hepatitis.
Severe skin reactions - rare cases of Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported. Immediate medical attention is required if blistering or widespread rash develops.
Neuropsychiatric events - depression, anxiety, or suicidal ideation may occur; patients with a history of mental illness should be evaluated closely.

Contraindications

Pregnancy (first trimester): Efavirenz is classified as a teratogen (Category D) due to documented neural-tube defects.
Severe hepatic impairment: Contraindicated because drug clearance is markedly reduced.
Known hypersensitivity to efavirenz or other NNRTIs.

Drug Interactions

Efavirenz is a moderate inducer of cytochrome P450 3A4 and 2B6, leading to reduced exposure of co-administered drugs such as:

Azole antifungals (e.g., ketoconazole) - may increase efavirenz levels, raising toxicity risk.
Rifampicin - can lower efavirenz concentrations, potentially compromising efficacy.
Other serotonergic agents - combined use may heighten the risk of serotonin syndrome.

Clinicians should review all concomitant medications, including over-the-counter products and herbal supplements, before initiating therapy.

Special Populations

Pregnancy: Efavirenz should be avoided in the first trimester; alternative regimens are preferred.
Breastfeeding: Limited data suggest low infant exposure; however, many guidelines advise against use while nursing.
Older adults: Age-related hepatic decline may necessitate dose adjustment.
Renal impairment: No dose change is required for mild to moderate dysfunction, but severe impairment warrants careful monitoring.

Frequently Asked Questions

How does efavirenz differ from nevirapine? Efavirenz has a longer half-life and is taken once daily, whereas nevirapine requires twice-daily dosing. Efavirenz is more likely to cause vivid dreams, while nevirapine carries a higher risk of severe liver toxicity.
How long does efavirenz take to work? Plasma drug levels stabilize within five days, and most patients see a measurable drop in HIV RNA within two weeks. Full virologic suppression is typically achieved by eight weeks of consistent therapy.
What foods should I avoid with efavirenz? High-fat meals can lower efavirenz absorption by up to 25 %. Taking the tablet on an empty stomach, preferably before bedtime, helps maintain optimal plasma concentrations.
Can I take efavirenz with my antidepressant? Efavirenz may increase the metabolism of certain antidepressants via CYP450 induction, potentially reducing their effectiveness. Discuss any psychiatric medications with your clinician to evaluate the need for dose adjustments.
What should I do if I experience vivid dreams or insomnia? These side effects often lessen after the first few weeks. If they persist, inform your healthcare provider; dose timing (bedtime) or temporary dose reduction may be considered under supervision.
Is efavirenz safe for people with mild liver disease? Mild hepatic impairment usually does not require dose modification, but liver function tests should be monitored regularly to detect any elevation in transaminases.
How does efavirenz interact with hormonal contraceptives? Efavirenz can reduce the efficacy of combined oral contraceptives by inducing metabolism, increasing the risk of breakthrough bleeding. Additional or alternative contraceptive methods are recommended.
Why is efavirenz classified as a teratogen? Studies have linked first-trimester exposure to neural-tube defects such as spina bifida. Consequently, regulatory agencies advise against its use during early pregnancy.
Can I buy efavirenz online in Singapore? Yes, efavirenz is available through our online pharmacy, which delivers discreetly and complies with HSA standards. Ensure you have a valid prescription from a licensed practitioner before ordering.
What information should I provide my doctor when discussing efavirenz?
- Complete medical history, including any liver or psychiatric conditions.
- Full list of current medications, supplements, and over-the-counter products.
- Recent laboratory results (e.g., liver enzymes, HIV viral load, CD4 count).
- Pregnancy status or plans for conception.

Disclaimer

The information provided about efavirenz is for general knowledge only. It does not replace professional medical consultation or the official prescribing information for medications containing this ingredient. All treatment decisions, including dosing, formulation selection, and monitoring, should be made under the supervision of a qualified healthcare provider who can assess individual medical history, current medications, and specific health needs. We assume all readers are responsible adults capable of making informed decisions about their health. Our online pharmacy offers access to medications containing efavirenz for individuals who may have limited availability through traditional pharmacies, prescription-based insurance schemes, or who are seeking affordable generic alternatives. Always consult your doctor before starting, changing, or discontinuing any medication containing efavirenz.