Efavirenz comes as single tablets. It is also part of some fixed dose combinations with tenofovir and lamivudine or emtricitabine. Your doctor picks the exact brand that fits your country rules and your lab profile.

How it works?

HIV needs an enzyme called reverse transcriptase. It uses this enzyme to copy its genetic material. Efavirenz binds to the enzyme at a special pocket. The enzyme stops working right. The virus struggles to make new copies. Viral load goes down when you take your pills on time. CD4 count can rise with time.

Who can use it?

• Adults and teens who meet weight and safety criteria.
• People starting therapy where efavirenz is part of the local first line plan.
• People switching from other plans when there is no resistance that blocks efavirenz.

Who should avoid or be careful

• Do not use if you had a severe allergy to efavirenz before.
• History of serious mental health issues needs careful review. Efavirenz can worsen mood or sleep in some people.
• Liver disease requires close checks.
• Seizure disorder needs caution.
• Pregnancy planning should be discussed early.

How to take Efavirenz

• Most adults take 600 mg once daily at bedtime.
• Take it on an empty stomach. Avoid a high fat meal near the dose. This simple step often lowers dizziness and strange dreams.
• Swallow the tablet whole with a glass of water.
• If you miss a dose, take it when you remember. If it is close to the next one, skip the missed dose. Do not double.
• Keep a daily alarm. A pill box helps.
• Drink water through the day. It helps overall health.

These are common patterns. Always follow your own prescription.

Drug interactions you must know

Efavirenz affects liver enzymes that handle many medicines. It can reduce or raise levels of other drugs. Interactions can be serious.

• Rifampin for TB can lower efavirenz levels. Some plans increase efavirenz dose. Your TB and HIV doctors will coordinate.
• Azole antifungals and macrolide antibiotics can interact. Doses may change or an alternative chosen.
• Benzodiazepines like midazolam and triazolam are not advised.
• Anticonvulsants such as carbamazepine, phenytoin, phenobarbital can lower efavirenz. Levels need checks or a switch.
• Hormonal contraceptives may work less well. Add a barrier method to prevent pregnancy.
• Warfarin and methadone levels can change. Monitoring and dose edits may be required.
• Direct acting hepatitis C antivirals may have issues with strong inducers. Your liver clinic will verify safety.
• Alcohol is not a drug interaction in the strict sense. Heavy drinking is still a bad idea. It can worsen sleep and liver stress.

Never start or stop a medicine without checking with your HIV doctor.

Side effects

• Dizziness or light headed feeling
• Trouble sleeping or vivid dreams
• Trouble with focus
• Feeling anxious or low mood
• Headache
• Nausea, stomach upset, diarrhea

Take the dose at bedtime on an empty stomach. If symptoms stay strong after two to four weeks, tell your doctor.

Monitoring and follow up

• Before start. Viral load, CD4, liver and kidney tests, pregnancy test when relevant, mental health history, and drug list review.
• After start. Viral load at 4 to 12 weeks. Then every 3 to 6 months.
• Check liver enzymes as advised.
• If you are on TB therapy or seizure medicines, plan extra checks.
• If sleep or mood do not settle, speak early. Do not wait.

Practical tips for everyday life

• Pair the dose with bedtime. Keep the stomach light or empty.
• If dreams are too strong, try a consistent sleep routine. Dark room. No screens late.
• Avoid driving or operating machines if you feel dizzy after the dose.
• Use condoms. Stay undetectable to protect your partner.
• Ask your clinic about vaccines. Flu, hepatitis, and others keep you safer.
• Keep a small note in your wallet with your medicines. Helps in emergencies.

Pregnancy, breastfeeding, and family planning

• Efavirenz has been used in pregnancy. Large datasets are more reassuring now. Many programs still prefer newer options when starting treatment in pregnancy. If you are planning a baby, tell your doctor. You will get a plan that keep both mother and baby safe.
• Hormonal birth control can be less effective with efavirenz. Use a barrier method as backup. This is important to avoid unplanned pregnancy while your regimen is being reviewed.

FAQs

Q.Does efavirenz cure HIV
No. It controls HIV when combined with other drugs. With steady use you can reach undetectable viral load.

Q. Can I take it with food
Better to take it on an empty stomach. A heavy meal can raise side effects.

Q.I feel dizzy in the morning. What do I do
Keep bedtime dosing. Keep the stomach light at night. Most people feel better in a few weeks. If not, call your doctor.

Q. Is the 400 mg dose real
Yes in some programs. The goal is similar efficacy with fewer side effects. Your clinic will judge if it fits your case.

Q. Can I drink alcohol
Small amounts may be fine for some. Heavy drinking is not advised. It worsens sleep and liver stress.

Sources

• U.S. DHHS Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents with HIV
• World Health Organization consolidated guidelines on HIV treatment and service delivery
• Efavirenz prescribing information from originator and approved generics
• British HIV Association treatment guidelines
• Patient drug monographs from 1mg, Apollo Pharmacy, and Drugs.com