Proper Use

Drug information provided by: IBM Micromedex

Take this medicine exactly as directed by your doctor. Do not take it more often, and do not take it for a longer time than your doctor ordered. Also, do not change the dose or stop taking this medicine without checking first with your doctor. When your supply of this medicine is running low, contact your doctor or pharmacist ahead of time. Do not allow yourself to run out of this medicine.

This medicine comes with a patient information insert. Read and follow the instructions carefully. Ask your doctor if you have any questions.

Keep taking efavirenz for the full time of treatment, even if you begin to feel better. It is also important that you continue taking all other medicines for HIV infection your doctor has instructed you to take. Efavirenz will not work if it is taken alone. It must be taken with other HIV medicines.

This medicine works best when there is a constant amount in the blood. To help keep blood levels constant, do not miss any doses. Also, it is best to take the doses at evenly spaced times during the day. For example, if you or your child are taking one dose per day, try to take it at the same time each day. If you need help planning the best times to take your medicine, check with your doctor.

Take this medicine on an empty stomach, preferably at bedtime. Swallow this medicine with water. Do not break, crush, or chew the tablets.

If you or your child cannot swallow capsules or tablets, you may open the capsule and pour the contents into a small amount of soft food (eg, applesauce, grape jelly, yogurt). You may also mix it with an infant formula for young children who cannot eat solid foods yet. It must be given within 30 minutes after it has been mixed. After the mixture has been given add small amount of food or formula to the empty container and gently stir to mix any capsule contents left in it. Do not eat anything else for 2 hours after taking this medicine with food or formula.

Tell your doctor if you take rifampin (Rifadin®, Rifamate®, Rifater®) or voriconazole (Vfend®). Your dose may need to be changed.


The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage forms (capsules or tablets):
    • For treatment of HIV infection:
      • Adults—600 milligrams (mg) once a day, taken with other medicines.
      • Children 3 months of age and older (by weight)—
        • 3.5 to 5 kilograms of body weight: 100 mg once a day, taken with other medicines.
        • 5 to 7.5 kilograms of body weight: 150 mg once a day, taken with other medicines.
        • 7.5 to 15 kilograms of body weight: 200 mg once a day, taken with other medicines.
        • 15 to 20 kilograms of body weight: 250 mg once a day, taken with other medicines.
        • 20 to 25 kilograms of body weight: 300 mg once a day, taken with other medicines.
        • 25 to 32.5 kilograms of body weight: 350 mg once a day, taken with other medicines.
        • 32.5 to 40 kilograms of body weight: 400 mg once a day, taken with other medicines.
        • 40 kilograms of body weight or over: 600 mg once a day, taken with other medicines.
      • Children up to 3 months of age—Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.


Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.