Efavirenz is an antiretroviral medicine that belongs to the class of medications called nonnucleoside reverse transcriptase inhibitors (NNRTIs). FDA approved this medication on 17 September 1998 for its medical use.

It is used in combination with other medications to treat human immunodeficiency virus (HIV) infection by reducing the amount of the virus in the blood. It is used by adults, adolescents, and children three months of age and older.  Although efavirenz does not cure HIV, it may decrease your chance of developing acquired immunodeficiency syndrome (AIDS) and HIV-related illnesses such as serious infections or cancer.

It is an orally available prescription drug. Your doctor will decide the dose and duration of efavirenz, based on the disease condition and other factors. Always take this medicine as prescribed by your doctor. Take the tablet at the same time. Taking the tablet on an empty stomach, preferably at bedtime, is recommended. An empty stomach is commonly defined as 1 hour before or 2 hours after a meal. Do not break, chew, crush, or break the tablet. Swallow the whole tablet with water.

The common side effects of efavirenz are rash, itchy skin, diarrhea, vomiting, dizziness, headache, insomnia, and tiredness. Other serious side effects include heart problems, severe, skin rashes, liver injury, neurotoxicity, mental problems, and suicidal thoughts.

This drug is intended to cause severe psychiatric symptoms, including severe depression, suicidal thoughts, aggression, hallucinations, and mood changes. Inform your physician immediately and seek medical advice if you face these symptoms. This medicine may cause hypersensitivity reactions ranging from mild to severe. These reactions may include rash, fever, blisters, oral lesions, facial swelling, and liver inflammation. Medical attention should be sought immediately if any signs of hypersensitivity are observed. 

Efavirenz can cause liver damage, including liver failure, in some cases. Patients with underlying liver disease or hepatitis B or C co-infection may be at increased risk. Liver function tests should be regularly monitored during treatment. This medicine may cause fetal harm if used during pregnancy, particularly during the first trimester. Inform your physician if you are pregnant or planning to become pregnant during the treatment.

Do not take efavirenz if you are allergic to efavirenz or any of the other ingredients of this medicine and if you have serious liver and heart disease. Inform your physician if you have liver diseases, heart problems, a family history of heart diseases, fits or seizures, and mental illness. Once you start taking this medicine, look for signs of f dizziness, difficulty sleeping, drowsiness, difficulty concentrating, skin rash, signs of inflammation or infection, bone problems, and abnormal dreaming. If you face any of these symptoms, report them to your doctor immediately. 

Efavirenz is not recommended for children under 3 months or weighing less than 3.5 kg. Inform your healthcare provider about all the medicines you take, including prescription, over-the-counter, nutritional supplements, and herbal products. Certain medications interact with efavirenz and reduce its effectiveness by causing undesirable side effects.

Store at 25°C. Protect the medicine from light and excessive moisture. Keep the medicine out of reach of children and pets. If you forgot to take the tablet, take your next dose at the scheduled time. Do not take a double dose to make up for a forgotten dose. Do not stop using this medicine without talking to your doctor first. If you stop the medicine, even for a short time, the virus may become harder to treat. Take this medicine on an empty stomach, preferably at bedtime. Swallow the capsule or tablet whole with water. Do not break, crush, or chew the tablet. It is not safe to take this medicine during pregnancy. It could harm an unborn baby.

Birth control pills may not work while you are using efavirenz, so do not use a hormone method as a form of birth control. Use a barrier method plus another type. Talk with your doctor about what choice is best for you. Your immune system may get stronger when you start taking an HIV medicine. This could cause a hidden infection in your body to become active. Tell your doctor right away if you notice any changes in your health. Your physician may advise you to do regular blood tests to monitor your disease condition and the effectiveness of the treatment.

1. EFAVIRENZ-HIGHLIGHTS of PRESCRIBING INFORMATION.; [Revised September 2011.] [Accessed May 11, 2023]. https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/020972s038lbl.pdf
2. Efavirenz 600mg film-coated tablets - Summary of Product Characteristics (SmPC) - (emc). www.medicines.org.uk. Published July 2022. Accessed May 11, 2023. http://www.medicines.org.uk/emc/product/7070/smpc
3. KD Tripathi, Essentials of Medical Pharmacology, Antiviral drugs,7th edition, 2013, 809.
4. Goodman & Gilman’s, The Pharmacological Basis of Therapeutics Antiretroviral agents and treatment of HIV infection, , 12th edition, 2011, 1643.

The drug information on this page is not a substitute for medical advice. It is meant for educational purposes only. For further details, consult your doctor about your medical condition to know if you can receive this treatment.