Efavirenz Medications

Efavirenz is an NNRTI antiretroviral that inhibits HIV reverse transcriptase. It is used in combination therapy to treat HIV-1 infection in adults and children.

Sustiva

Efavirenz

$3.87 per pill

200 | 600mg

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About Efavirenz

Efavirenz is a non-nucleoside reverse-transcriptase inhibitor (NNRTI) that forms a core component of combination antiretroviral therapy (cART) for adults living with HIV-1 infection. By binding directly to the HIV-1 reverse transcriptase enzyme, it halts viral RNA synthesis, a step essential for viral replication. Efavirenz is marketed globally under brand names such as Sustiva, Stocrin and generic formulations, all of which are listed on the Therapeutic Goods Administration (TGA) database for Australia. While its primary indication is the treatment-naïve adult population, clinicians sometimes incorporate it into second-line regimens when resistance patterns or tolerability issues arise. Off-label, efavirenz has been explored for pharmacokinetic boosting of other agents, though such use remains investigational. Across numerous randomized trials, efavirenz-containing regimens have achieved durable viral suppression in >80 % of participants, establishing the drug as a mainstay of modern HIV management.

What is efavirenz?

Efavirenz belongs to the NNRTI class, which interferes with the reverse transcription step of the HIV life cycle. The Australian TGA approved efavirenz in 1999 for use in combination with two nucleoside reverse-transcriptase inhibitors (NRTIs) as first-line therapy for adults with HIV-1. The U.S. FDA and the European Medicines Agency later endorsed the same indication, and the World Health Organization includes efavirenz in its preferred first-line regimen list. At the molecular level, efavirenz lodges in a hydrophobic pocket of the reverse transcriptase enzyme, inducing a conformational change that prevents incorporation of nucleotides and terminates DNA chain elongation. The drug is supplied as 600 mg film-coated tablets, available both as the branded product Sustiva and as widely distributed generics, which can be purchased from our online pharmacy.

How efavirenz works

Mechanism of action

Efavirenz binds reversibly to a non-active site on HIV-1 reverse transcriptase. This allosteric interaction distorts the enzyme’s active site, inhibiting the addition of nucleotides to the growing viral DNA strand. The inhibition is “non-competitive,” meaning that efavirenz remains effective even when intracellular nucleoside concentrations fluctuate.

Therapeutic effects

By stopping reverse transcription, efavirenz blocks the production of proviral DNA that would otherwise integrate into the host genome. The resulting decline in plasma viral load allows the immune system to recover, as reflected by rising CD4 + T-cell counts. Clinically, patients experience reduced opportunistic infections and improved quality of life.

Onset and duration

Peak plasma concentrations are reached 3-5 hours after oral dosing, and steady-state levels are typically achieved after 10-14 days of daily administration. The antiviral effect becomes measurable within the first week, with most patients attaining undetectable viral loads by week 12 when efavirenz is part of a fully suppressive regimen. The drug’s half-life averages 40-55 hours, supporting once-daily dosing.

Approved uses and applications

Approved indications

Initial cART for treatment-naïve adults with HIV-1, combined with two NRTIs (TGA, FDA, WHO).
Switch therapy in patients with documented resistance to other NNRTIs, provided susceptibility tests confirm efavirenz activity.

Off-label uses

Pharmacokinetic enhancer for certain antiretrovirals (e.g., ritonavir-boosted protease inhibitors) in research settings; not officially sanctioned by the TGA.
Neurocognitive studies exploring efavirenz’s impact on central nervous system function; these investigations remain experimental.

Clinical efficacy

The ACTG 5142 trial, published in The New England Journal of Medicine, showed that efavirenz-based regimens achieved a 78 % virologic suppression rate at week 48, compared with 71 % for protease-inhibitor-based arms. The Lancet HIV-1 study reported a median increase of 150 cells/µL in CD4 count after 96 weeks of efavirenz therapy, underscoring its durability.

Buying efavirenz from our online pharmacy

Why choose our service

Accessing efavirenz can be challenging in remote Australian regions where specialist pharmacies are scarce. Our pharmacy service delivers the medication directly to your door, preserving confidentiality and reducing travel time.

Brand names and generic options

Sustaina (brand) - 600 mg
Stocrin (brand) - 600 mg
Generic efavirenz - 600 mg

Generic tablets provide the same clinical effect at a fraction of the cost, and our platform highlights the price difference so you can make an informed choice.

Quality & safety

We partner with licensed international pharmacies that operate under stringent regulatory frameworks and adhere to WHO Good Manufacturing Practice standards.

Pricing & access

Competitive pricing starts at AU$5 per tablet for generics, with a lifetime 10 % discount on all reorders when you create an account.

Discreet delivery

Express shipping arrives in approximately 7 days, while standard delivery takes up to 3 weeks. Every package is sealed in unmarked, protective material to ensure privacy.

Dosing, formulations & administration

Available formulations

Efavirenz is supplied as 600 mg film-coated tablets, the only commercially approved strength in Australia.

Typical dosing ranges

For adults initiating therapy, clinicians often start with 600 mg once daily taken at bedtime. In cases of drug-drug interactions that raise efavirenz levels, the dose may be reduced to 400 mg after therapeutic drug monitoring, as recommended by the TGA.

Administration guidelines

Take the tablet with a light snack or after an empty stomach to minimize gastrointestinal irritation.
Because efavirenz can cause vivid dreams, bedtime dosing helps mitigate sleep disturbances.
Avoid concurrent use of strong CYP2B6 inhibitors (e.g., ritonavir) without dose adjustment.

A qualified healthcare professional must determine the exact dose based on viral load, resistance profile, and individual metabolic factors.

Safety profile & considerations

Common side effects

Central nervous system effects (dizziness, vivid dreams, insomnia) - reported in >10 % of patients.
Rash - occurs in 5-8 % of users, usually mild.
Elevated liver enzymes - seen in 5 % of participants; routine monitoring is advised.

Serious adverse events

Severe psychiatric reactions (depression, suicidal ideation) are rare (<1 %) but require immediate medical attention.
Stevens-Johnson syndrome - extremely uncommon, necessitating prompt discontinuation.

Contraindications

Known hypersensitivity to efavirenz or any tablet excipients.
Pregnant women at the first trimester, due to potential teratogenicity (category D).

Drug interactions

CYP2B6 inducers (e.g., carbamazepine) lower efavirenz concentrations, risking virologic failure.
CYP2B6 inhibitors (e.g., ritonavir, fluconazole) raise levels and may intensify CNS side effects; dose reduction is often required.
Other NNRTIs - co-administration is contraindicated because of overlapping toxicity.

Special populations

Pregnancy & breastfeeding: Efavirenz is discouraged during the first trimester; alternative regimens are preferred.
Older adults: Age-related hepatic decline may prolong half-life; start at the standard dose but monitor plasma levels.
Renal or hepatic impairment: No dose adjustment needed for mild to moderate dysfunction, but severe hepatic disease warrants careful monitoring.

Frequently Asked Questions

How does efavirenz differ from nevirapine? Efavirenz has a longer half-life, allowing once-daily dosing, whereas nevirapine requires twice-daily administration. Efavirenz also exhibits a higher barrier to resistance but is more frequently associated with CNS side effects.
How long before efavirenz produces noticeable effects for viral suppression? Plasma viral load typically falls by half within the first week, and most patients achieve undetectable levels by week 12 when combined with two NRTIs.
What should I do if I experience vivid dreams after taking efavirenz? Report the symptom to your clinician; they may suggest taking the dose at bedtime or, if intolerable, switching to an alternative NNRTI.
Can I take efavirenz with food? Taking efavirenz with a light snack reduces gastrointestinal irritation and can slightly improve absorption, but a high-fat meal is not required.
Is efavirenz safe for people with mild liver disease? Yes, mild hepatic impairment does not usually require dose adjustment, though liver function tests should be monitored regularly.
What foods should I avoid while on efavirenz? There are no specific dietary restrictions, but grapefruit juice can inhibit CYP3A4 and may modestly increase efavirenz levels; moderation is advisable.
How does efavirenz affect cholesterol or lipid profiles? Efavirenz modestly raises total cholesterol and triglycerides in some patients; lipid monitoring is recommended, especially when combined with protease inhibitors.
Can efavirenz be used in individuals over 65 years old? Yes, but older adults may be more susceptible to CNS adverse events; clinicians often start at the standard dose and assess tolerability closely.
What monitoring is required after starting efavirenz? Baseline and periodic liver function tests, plasma HIV-1 RNA levels, CD4 counts, and assessment for neuropsychiatric symptoms are standard.
What information should I provide my doctor when discussing efavirenz?
- Complete list of current medications, including over-the-counter drugs and supplements.
- History of psychiatric illness or seizure disorders.
- Recent liver function test results.
- 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.