Efavirenz: Patient Guide for Use in Australia
Basic Product Information
- International Non-proprietary Name (INN): Efavirenz
- Australia Brand Names: Stocrin®, Efexor® (note: verify current brands at your pharmacy; Efexor is also a brand for another medicine—always check active ingredient)
- ATC Code: J05AG03 (Antivirals for systemic use, non-nucleoside reverse transcriptase inhibitors)
- Available Forms and Strengths: Tablets (50 mg, 200 mg, 600 mg); Capsules (50 mg, 200 mg) — most commonly 600 mg tablets, sometimes in combination tablets
- Manufacturers: Merck Sharp & Dohme (Australia) Pty Ltd, Mylan, Teva, and various generics
- Prescription Status: Schedule 4 (Prescription Only Medicine), available only with a valid doctor’s prescription in Australia
Mechanism of Action
For Patients: Efavirenz helps to fight HIV (human immunodeficiency virus) by blocking an enzyme called reverse transcriptase. This slows down the virus's ability to multiply, which helps control your HIV infection and protects your immune system.
For Specialists: Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI) that binds directly to HIV-1 reverse transcriptase, causing a conformational change and inhibiting its activity. This prevents viral RNA-dependent DNA synthesis.
Pharmacokinetics
- Absorption: Rapid, with peak plasma concentrations 3–5 hours after oral administration.
- Metabolism: Hepatic, primarily via CYP2B6 and CYP3A4.
- Elimination: Mainly as metabolites in urine and faeces (urinary excretion of parent drug is minimal).
- Duration of Action: Terminal half-life is approximately 40–55 hours, supporting once-daily dosing.
Use in Everyday Life and Best Practices
- Usual Adult Dose: 600 mg once daily, usually taken in combination with other antiretroviral agents.
- How to Use: Take exactly as prescribed, at the same time every day, to maintain steady levels in your body.
- Context in Australia: Always have regular check-ups with your GP or HIV specialist. Discuss any problems with your pharmacist or healthcare team. Never stop Efavirenz suddenly unless told by your doctor, as this can lead to drug resistance.
- Do not share: Your medicine is for you only—do not give it to others, even if they have similar symptoms.
Dosing in the Morning vs Evening
- When to take: Efavirenz is usually recommended at bedtime to reduce side effects like dizziness, drowsiness, or vivid dreams.
- Advantages of evening dosing:
- May lessen central nervous system (CNS) effects such as anxiety, trouble sleeping, and confusion—taking at bedtime means you’re likely to be asleep when these occur.
- Disadvantages:
- CNS side effects may persist into the next day for some people. If you feel groggy in the morning, discuss the timing with your doctor.
- Tips: Take Efavirenz at the same time each day. If you miss a dose, take it as soon as you remember, unless it’s nearly time for your next dose—then skip the missed dose (never double doses).
Taking With Food or on an Empty Stomach
- Australian guidance: Take Efavirenz on an empty stomach (either 1 hour before or 2 hours after food).
- With meals? Taking Efavirenz with food, especially high-fat meals, can increase the risk of side effects like dizziness and confusion by raising drug levels in the blood.
- Common dietary advice in Australia: Try to take Efavirenz at bedtime without food or just with a small snack, following typical evening meal patterns in Australia. Avoid heavy, fatty meals before taking your dose.
Interaction Warnings
| Type | Example(s) | Effect/Advice |
|---|---|---|
| Food | High-fat meals, oily snacks | Increased side effects due to higher Efavirenz blood levels—take on empty stomach |
| Alcohol | All types | May worsen dizziness/confusion—limit or avoid |
| Medications | St John’s Wort, voriconazole, oral contraceptives, rifampicin, anti-seizure medications | Can reduce Efavirenz effectiveness or increase side effects—discuss all medicines and supplements with your doctor/pharmacist |
| Herbal Supplements | St John’s Wort | May reduce Efavirenz effectiveness—avoid |
Indications
| Indication | Approved/Off-label | Notes |
|---|---|---|
| HIV-1 infection (adults & children ≥3 months, >3.5 kg) | Approved | First-line antiretroviral therapy, always in combination |
| Post-exposure prophylaxis (PEP) | Off-label | Used in some regimens, not routine |
| HIV-2 infection | Off-label | Not effective—do not use |
Dosing According to Clinical Indications
| Population | Indication | Typical Dose | Notes |
|---|---|---|---|
| Adults | HIV-1 infection, combination therapy | 600 mg once daily | Usually at bedtime, with two other antiretroviral medications |
| Children (≥3 months & >3.5 kg) | HIV-1 infection, combination therapy | 9–17 mg/kg once daily (maximum 600 mg) | Dose based on weight; use by paediatric specialist guidance |
| Elderly | HIV-1 infection, combination therapy | 600 mg once daily (if normal liver/kidney function) | Monitor closely for CNS effects |
| Liver Impairment | Dosage reduction often required | Specialist review and monitoring essential |
Safety Profile & Side Effects
| Frequency | Side Effect | Advice |
|---|---|---|
| Common (≥1 in 10) | Dizziness, trouble sleeping, vivid dreams, headache | Usually mild, often reduce after 2–4 weeks |
| Common | Rash (mild), fatigue, nausea | Tell your doctor if persistent or severe |
| Uncommon (≤1 in 100) | Liver issues (yellow skin/eyes, dark urine) | See your doctor promptly |
| Rare (≤1 in 1000) | Severe skin reactions (blistering rash), mood changes, depression, seizures | Seek emergency help |
Warnings: Risk of severe allergic reactions, psychiatric symptoms (suicidal thoughts, paranoia), and liver damage—report any major mood changes or symptoms quickly.
Guidelines for Proper Use
- Take at bedtime, on an empty stomach, unless otherwise advised by your doctor.
- Swallow whole with water (do not break, crush, or chew)
- Adhere closely to your dosing schedule. Missing doses increases risk of resistance.
- Attend regular blood tests as advised to check for side effects or interactions.
- Alcohol and recreational drugs can worsen side effects—reduce or avoid use.
- If pregnant or planning pregnancy, notify your healthcare provider—Efavirenz should be avoided early in pregnancy if possible (risk of birth defects).
- Store Efavirenz below 25°C, protected from moisture; keep out of reach of children.
- Discuss all supplements, non-prescription medicines, or herbal remedies with your doctor/pharmacist.
Alternative Treatment Options
- Other NNRTIs: Rilpivirine (Edurant®), Doravirine (Pifeltro®)—generally fewer CNS side effects, but different drug interaction profiles.
- Integrase Inhibitors: Dolutegravir (Tivicay®), Bictegravir (in combination products)—highly effective, well tolerated; now often first-line in Australia.
- Protease Inhibitors: Darunavir (Prezista®), Atazanavir (Reyataz®), typically used in certain resistance settings or intolerance to other drugs.
- Combination products: Atripla® (Efavirenz/Emtricitabine/Tenofovir) and other fixed-dose combinations may offer once-daily convenience.
Newer regimens are often preferred due to better side effect profiles and lower pill burden. All alternatives are available on the Pharmaceutical Benefits Scheme (PBS) for eligible patients in Australia.
Legal, Registration, and Reimbursement Status in Australia
- Legal Category: S4 (Prescription Only)
- Registration: Registered with the Therapeutic Goods Administration (TGA), Australia
- Reimbursement: Listed on the PBS for eligible indications—subsidised prescriptions for Australian residents
- Prescription requirements: Written by a registered Australian medical practitioner, ongoing prescribing typically managed by a specialist or GP with HIV experience
Latest Research/Clinical Guidance (2022–2025)
- Australian HIV guidelines (ASHM, 2024): Recommend integrase inhibitors as first-line, with Efavirenz-based regimens considered in certain cases (e.g., intolerance, drug resistance, or access issues).
- International guidelines (WHO, 2023; EACS, 2024): Continue to list Efavirenz as alternative option, not generally recommended for new patients due to CNS side effects and inter-patient variability.
- Recent studies confirm equivalence of once-daily Efavirenz to newer regimens in viral suppression, but higher rates of side effects and treatment discontinuation.
- References:
- ASHM HIV Management Guidelines. Sydney: ASHM; updated 2024. https://ashm.org.au
- WHO Consolidated Guidelines on HIV. Geneva: WHO; 2023.
- Australian Department of Health, PBS Publications. 2024.
Availability and Delivery
| Pack Size | Typical Content | Indicative PBS Patient Cost (2024)* |
|---|---|---|
| 30 tablets | 600 mg, one-month supply | A$30–A$40 (PBS general scripts); concession cards—less |
| 60 tablets | 600 mg, two-month supply | A$60–A$80 |
| Generic packs | Varies (consult pharmacy) | May be lower |
Delivery to Major Australian Cities (indicative, after pharmacy filling):
| Location | Approx Delivery Time |
|---|---|
| Sydney, Melbourne, Brisbane | 1–2 working days |
| Perth, Adelaide, Canberra | 2–3 working days |
| Darwin, Hobart, regional/rural | 3–5 working days |
| Remote or Indigenous communities | Up to 7 working days (allow extra time) |
*Prices and times subject to change. Check with your pharmacy for current details and expedited shipping options.
FAQ – Most Common Patient Questions
- What if I miss a dose of Efavirenz?
Take it as soon as you remember, unless it's nearly time for your next dose. In that case, skip the missed dose. Do not double up. If you miss more than one dose, contact your doctor or pharmacist. - Can Efavirenz cure HIV?
No, Efavirenz does not cure HIV, but it helps control the virus, keeps your immune system stronger, and reduces the risk of transmission. It must be taken regularly with other antiretroviral medicines as prescribed. - Is it safe to drink alcohol?
Alcohol can increase Efavirenz-related side effects such as dizziness and confusion. If you choose to drink, keep it to a minimum and never mix heavy drinking with your medication. - Can I take Efavirenz during pregnancy?
There is a risk of birth defects if used in the first trimester. If you are pregnant or planning to be, tell your doctor immediately to discuss safer alternatives or careful monitoring. - Where can I get more advice?
Your GP, local HIV clinic, or pharmacist can provide confidential advice. For more, visit the ASHM HIV Resources site or the Australian Government HIV website.
This summary is not a substitute for individual medical advice. Always follow your doctor’s instructions and consult your healthcare team for personal questions.
