Efavirenz Dosage

This dosage information may not include all the information needed to use Efavirenz safely and effectively. See additional information for Efavirenz.

The information at Drugs.com is not a substitute for medical advice. ALWAYS consult your doctor or pharmacist.

Usual Adult Dose for:

Usual Pediatric Dose for:

Additional dosage information:

Usual Adult Dose for HIV Infection

600 mg orally once a day

Usual Adult Dose for Nonoccupational Exposure

(Not approved by FDA)

Centers for Disease Control and Prevention (CDC) recommendations: 600 mg orally once a day
Duration of therapy: 28 days

-Efavirenz should be used in combination with (lamivudine or emtricitabine) plus (zidovudine or tenofovir).
-Prophylaxis should be initiated as soon as possible, within 72 hours of exposure.

Usual Adult Dose for Occupational Exposure

(Not approved by FDA)

CDC recommendations: 600 mg orally once a day
Duration of therapy: Generally 28 days; however, the exact duration of therapy may differ based on the institution's protocol.

-Recommended as an alternate expanded regimen for HIV postexposure prophylaxis
-Efavirenz should be used in combination with (lamivudine plus zidovudine) or (emtricitabine plus zidovudine) or (lamivudine plus tenofovir) or (emtricitabine plus tenofovir).
-Prophylaxis should be initiated immediately, preferably within hours after exposure.

Usual Pediatric Dose for HIV Infection

3 months or older:
3.5 to less than 5 kg: 100 mg orally once a day
5 to less than 7.5 kg: 150 mg orally once a day
7.5 to less than 15 kg: 200 mg orally once a day
15 to less than 20 kg: 250 mg orally once a day
20 to less than 25 kg: 300 mg orally once a day
25 to less than 32.5 kg: 350 mg orally once a day
32.5 to less than 40 kg: 400 mg orally once a day
40 kg or more: 600 mg orally once a day

Renal Dose Adjustments

No adjustment recommended.

Liver Dose Adjustments

Mild liver dysfunction: Caution recommended.
Moderate to severe liver dysfunction: Not recommended.

Dose Adjustments

Concomitant voriconazole: The efavirenz dose should be decreased to 300 mg orally once a day using the capsule formulation.

Concomitant rifampin in patients weighing at least 50 kg: The efavirenz dose should be increased to 800 mg orally once a day.


Consult WARNINGS section for dosing related precautions.


No adjustment recommended.

Other Comments

Administration advice:
-Take on an empty stomach; administration with food increases efavirenz levels and may lead to increased rate of side effects.
-Take at bedtime to improve tolerability of central nervous system (CNS) side effects.
-Tablets must not be crushed.
-Capsules can be taken intact or as sprinkles.
-For patients unable to swallow capsules or tablets, the capsule contents can be taken with a small amount (1 to 2 teaspoons) of food; consult the manufacturer's product information regarding administration using the sprinkle method.

Reconstitution/preparation techniques:
-The manufacturer's product information should be consulted regarding preparation for the capsule sprinkle method of administration.

-Efavirenz should always be used in combination with other antiretroviral agents.

-General: Pregnancy testing (before starting efavirenz)
-Hepatic: Liver enzymes (before and during therapy)
-Metabolic: Triglycerides and cholesterol (before and periodically during therapy)

Patient advice:
-Efavirenz may impair the mental abilities needed to perform potentially hazardous tasks, such as driving or operating machinery; CNS effects may be additive if used with alcohol or psychoactive drugs.