Efavirenz is used together with other medicines to treat Human Immunodeficiency Virus type 1 (HIV-1) infection.
This medicine is not a cure for HIV infection. It only helps to keep the virus in check and can help improve the quality of life. It does not prevent the spread of HIV to other people.
Take Efavirenz exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.
Take this medicine on an empty stomach, preferably at bedtime. Try to take it at the same time each day.
Efavirenz is available as a tablet, capsule or as an oral solution.
If you have been given the tablet or capsule, swallow it whole with a glass of water. Do not divide, chew or crush the tablet.
For those who have difficulty in swallowing, you may carefully open the capsule, sprinkle and mix the contents with 1-2 teaspoons of soft foods such as applesauce, grape jelly, yogurt, or 10 mL of room temperature infant formula. To make sure that all of the medicine is taken, add about 2 teaspoons of the soft food on the container, stir the food to disperse any remaining residue, then take it immediately. Take the mixture within 30 minutes of mixing. Do not store the mixture for future use. Do not consume any additional food for 2 hours after taking your dose.
If you have been given the oral solution, use the measuring spoon, cup, or dropper provided to measure your dose.
The dose of this medicine will be decided by your doctor. Your doctor will advise you on the treatment timeframe depending on your condition and response to the medication.
Efavirenz must be taken regularly for it to be effective. Continue taking this medicine even when you feel better. Do not stop taking it unless instructed by the doctor.
Do not skip any doses. You must complete the entire course of medicine. If you don't, the infection will not be properly controlled.
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.
DO NOT double a dose under any circumstances.
If you often forget to take your medicine, let your doctor and pharmacist know.
Do not take this medicine if you ever had an allergic reaction (rashes, breathlessness, swollen eyes) to Efavirenz or other similar antiviral medications.
Alert your doctor if you have the following conditions:
- severe liver disease
- with or a family history of severe heart disease e.g. heart attack or heart failure
- with or a family history of heart rhythm disorders e.g. slow heartbeat
- imbalance of potassium or magnesium levels in the body
- with or a history of severe skin reactions e.g. rashes with skin peeling or blistering
as Efavirenz may not be suitable for you.
Do not take this medicine if you are on your 1st trimester of pregnancy. If you become pregnant while on Efavirenz therapy, alert your doctor immediately. This medicine may cause harm to your unborn child.
It is important that you do not get pregnant while taking this medicine. You must use proven birth control methods during Efavirenz therapy and for 12 weeks after stopping the treatment. Birth control medicines containing hormones alone may not be effective. You may wish to discuss other additional reliable methods of birth control with your doctor.
Do not breastfeed while you are being treated with this medicine.
Do not take Efavirenz with certain antibiotics and medicines for fungal or liver infections, irregular heartbeat, chest pain, cold or allergy, migraine, mood disorder, depression, digestive problems, malaria, opiate addiction, and certain herbal supplement. Please see section “Can I take this with other medicines?” below for more information.
Inform your doctor if you have the following conditions:
- with or a history of epilepsy (fits or seizures)
- history of mental illness including depression
- history of substance abuse
- dementia (group of symptoms affecting thinking and social abilities) associated with HIV
- with or a history of hepatitis B or C (contagious liver infection caused by a virus and spread through contaminated blood and body fluids)
- mild liver disease
- severe kidney disease
Let your doctor know if you are on your 2nd-3rd trimester of pregnancy.
It is best that you do not breastfeed as HIV passes into the breast milk. Avoid breastfeeding in order to reduce the risk of passing HIV to your baby. It is recommended to give your baby commercial infant formula provided that you have access to clean water and facilities.
Be sure to check with your doctor or pharmacist before giving Efavirenz to a child.
This medicine is not a cure for HIV. It only helps to slow down the development of HIV infection.
Efavirenz does not reduce your risk of passing the HIV infection to others through sexual contact or through contamination with infected blood. Ensure that you use proper precautions to avoid spreading HIV to others.
Both this medicine and HIV may weaken your immune system, leaving you more vulnerable to infections. Avoid crowded places and people who are sick to minimise the risk of catching an infection. While undergoing treatment, you may develop other infections or experience other health problems. Always keep your doctor updated on your condition and go for your appointed check-ups.
If you are going for certain laboratory tests (e.g. tests for cannabinoid or benzodiazepine), inform your doctor that you are taking Efavirenz.
A certain enzyme called CYP2B6 is involved in the metabolism of this medicine. Individuals who are intermediate and poor metabolisers of CYP2B6 may experience enhanced side effects of Efavirenz and may require dose adjustments. Although not routinely done, your doctor may advise you to undergo genetic testing to check if this medicine is best suited for you. If you know you have this gene type, inform your doctor.
Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly.
- You may need to have routine blood tests (e.g. liver function tests, blood cholesterol and sugar levels, amount of HIV in blood sample) while you are being treated with Efavirenz. Your doctor will advise you about how often you will need to have these tests.
- Monitoring of signs of infection, mood and behaviour disorders may also be needed.
Efavirenz may cause dizziness, drowsiness or impaired concentration. If affected, do not drive or take part in any activity in which you need to be alert.
Other side effects include any of the following: headache, nausea, vomiting, diarrhoea, stomach pain, tiredness, difficulty in controlling or coordinating movements, difficulty sleeping, abnormal dreams, and skin rash or itching.
Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
- rashes, breathlessness, swollen eyes, mouth or throat
- severe persistent stomach pain, unusual tiredness, yellowing of the skin or eyes
- chest pain or tightness, fast or irregular heartbeat
- hallucinations (seeing, hearing or feeling things that are not existent)
- unusual changes in mood or behaviour (being too depressed, agitated, or having compulsive and impulsive behaviour)
- having thoughts of self-harm
- rashes with peeling or blistering of the skin, lips, mouth, eyes or genitals accompanied by fever
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Do not take Efavirenz with the following medicines:
- certain antibiotics e.g. macrolides, fluoroquinolones, imidazole
- medicines for fungal infections e.g. triazole
- medicines for liver (hepatitis C) infection e.g. elbasvir, grazoprevir
- flecainide (medicines for irregular heartbeat)
- bepridil (medicine for chest pain)
- medicines for cold or allergy e.g. astemizole, terfenadine
- medicines for anxiety e.g. midazolam, triazolam
- medicines for migraine e.g. ergotamine, ergometrine, dihydroergotamine
- pimozide (medicine for mood disorders)
- medicines to treat depression e.g. imipramine, amitriptyline
- cisapride (medicine for digestive problems)
- medicines used to treat malaria e.g. atovaquone, proguanil
- methadone (medicine to treat opiate addiction)
- St. John's wort (herbal supplement)
Inform your doctor and pharmacist if you are taking any of these medicines:
- other medicines for HIV infections e.g. atazanavir, ritonavir, lopinavir, indinavir, maraviroc
- medicines for Hepatitis C infection e.g. glecaprevir, pibrentasvir, telaprevir, velpatasvir, sofosbuvir, voxilaprevir, boceprevir
- medicines for heart disease or high blood pressure e.g. diltiazem, verapamil, felodipine
- medicines used to treat tuberculosis or TB e.g. rifampicin, rifabutin
- medicines to treat fungal infections e.g. itraconazole, voriconazole, posaconazole
- medicines used to treat malaria e.g. artemether, lumefantrine
- medicines to treat depression e.g. sertraline, bupropion
- medicines used in organ transplant or certain immune disorders e.g. ciclosporin, tacrolimus
- medicines for epilepsy (fits or seizures) e.g. carbamazepine, phenytoin, phenobarbital
- blood-thinning medicines e.g. warfarin, acenocoumarol
- cholesterol-lowering medicines e.g. simvastatin, atorvastatin, pravastatin
- birth control pills e.g. ethinyloestradiol, norgestimate, etonorgestrel
This list does not include all medicines that may interact with Efavirenz.
Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements and medicines that you buy without a prescription.
Avoid alcohol and grapefruit juice.
Avoid Ginkgo biloba extracts.
It is important for you to maintain a healthy, low-fat and balanced diet.
Store in a cool, dry place away from the reach of children.
Medicines must not be used past the expiry date.