Efavirenz Dosage

Medically reviewed by Drugs.com. Last updated on Apr 4, 2025.

Usual Adult Dose for HIV Infection

600 mg orally once a day

Comments:

• This drug should be used with a protease inhibitor and/or NRTIs.

Use: In combination with other antiretroviral agents, for the treatment of HIV-1 infection

Usual Adult Dose for Nonoccupational Exposure

US CDC Recommendations: 600 mg orally once a day
Duration of therapy: 28 days

Comments:

• Only with expert consultation, as part of an alternative antiretroviral regimen for use as HIV nonoccupational postexposure prophylaxis (nPEP)
• This drug is contraindicated as nPEP in pregnant patients; it should be avoided in nPEP regimens during the first trimester and should not be used for patients of childbearing potential who might become pregnant during antiretroviral prophylaxis.
• Prophylaxis should be started as soon as possible, within 72 hours of exposure.
• Current guidelines should be consulted for additional information.

Usual Adult Dose for Occupational Exposure

US Public Health Service Working Group Recommendations: 600 mg orally once a day
Duration of therapy: 28 days, if tolerated

Comments:

• Only with expert consultation, as part of an alternative antiretroviral regimen for use as HIV postexposure prophylaxis
• Prophylaxis should be started as soon as possible, preferably within hours after exposure.
• The optimal duration of prophylaxis is unknown and may differ based on institution protocol.
• Current guidelines should be consulted for additional information.

Usual Pediatric Dose for HIV Infection

3 months and older:

• Weight 3.5 to less than 5 kg: 100 mg orally once a day
• Weight 5 to less than 7.5 kg: 150 mg orally once a day
• Weight 7.5 to less than 15 kg: 200 mg orally once a day
• Weight 15 to less than 20 kg: 250 mg orally once a day
• Weight 20 to less than 25 kg: 300 mg orally once a day
• Weight 25 to less than 32.5 kg: 350 mg orally once a day
• Weight 32.5 to less than 40 kg: 400 mg orally once a day
• Weight at least 40 kg: 600 mg orally once a day

Use: In combination with other antiretroviral agents, for the treatment of HIV-1 infection

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Mild liver dysfunction: No adjustment recommended; caution recommended.
Moderate or severe liver dysfunction (Child-Pugh B or C): Not recommended

If hepatotoxicity develops during therapy:

• Persistent elevations of serum transaminases to greater than 5 times the upper limit of normal: Consider discontinuation of this drug.
• Elevation of serum transaminases accompanied by clinical signs/symptoms of hepatitis or hepatic decompensation: Discontinue this drug.

Comments:

• Careful monitoring is recommended for patients with mild liver dysfunction; this drug should be administered with caution to such patients.

Dose Adjustments

Adult patients:

• If coadministered with voriconazole (maintenance dose increased to 400 mg orally every 12 hours): Decrease the efavirenz dose to 300 mg orally once a day using the capsule formulation; the manufacturer product information should be consulted.
• If coadministered with rifampin in patients weighing at least 50 kg: Increase the efavirenz dose to 800 mg orally once a day.

Precautions

CONTRAINDICATIONS:

• History of clinically significant hypersensitivity (e.g., Stevens-Johnson syndrome, erythema multiforme, toxic skin eruptions) to the active component or any of the ingredients
• Coadministration with elbasvir and grazoprevir

Safety and efficacy have not been established in pediatric patients weighing less than 3.5 kg or younger than 3 months; this drug is not recommended for use in these patients.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Comments:

• This drug is highly protein-bound; significant removal via dialysis is unlikely.

Other Comments

Administration advice:

• Monitor hepatic function before and during therapy.
• Administer on an empty stomach, preferably at bedtime; administration with food increases drug levels and may increase frequency of adverse reactions.
• Administration at bedtime may improve tolerability of nervous system symptoms.
• Swallow tablets intact with liquid; do not crush or break the tablets.
• Capsules can be swallowed intact with liquid or administered using the capsule sprinkle method.
• For patients unable to swallow capsules or tablets: The capsule contents may be administered with a small amount (1 to 2 teaspoons) of food; use of infant formula for mixing should only be considered for young infants who cannot reliably consume solid foods.
• After administration of the drug mixture, add an additional small amount (about 2 teaspoons) of food or formula to the empty mixing container, stir to disperse any remaining drug residue, and administer to the patient.
• Administer the drug mixture within 30 minutes of mixing.
• Do not consume any additional food for 2 hours after administration of this drug.
• Consult the manufacturer product information for further instructions on the capsule sprinkle method of administration.
• If a dose is missed, take it as soon as remembered; if it is almost time for the next dose, skip the missed dose and take the next dose at the regularly scheduled time. Do not take 2 doses at the same time.

Storage requirements:

• Store at 25C (77F); excursions permitted to 15C to 30C (59F to 86F).

Reconstitution/preparation techniques (for the capsule sprinkle method of administration):

• Open the capsule carefully to avoid spillage or dispersion of the capsule contents into the air; hold the capsule horizontally over a small container and carefully twist to open.
• For patients able to tolerate solid foods: In the small container, gently mix the entire capsule contents with a small amount (1 to 2 teaspoons) of an age-appropriate soft food (e.g., applesauce, grape jelly, yogurt).
• For young infants receiving the capsule sprinkle-infant formula mixture: In the small container, gently mix the entire capsule contents into 2 teaspoons of reconstituted room temperature infant formula by carefully stirring with a small spoon, then draw up the mixture into a 10 mL oral dosing syringe for administration.
• The manufacturer product information should be consulted.

General:

• This drug should always be used in combination with other antiretroviral agents; it should not be used as a single agent to treat HIV-1.
• This drug should not be added on as a sole agent to a failing regimen.

Monitoring:

• General: Pregnancy testing (before starting this drug)
• Hepatic: Liver enzymes (before and during therapy); hepatic function (before and during therapy)
• Metabolic: Triglycerides and cholesterol (before and periodically during therapy)

Patient advice:

• Read the US FDA-approved patient labeling (Patient Information and Instructions for Use).
• This drug may impair mental abilities needed to perform potentially hazardous tasks (e.g., driving, operating machinery); CNS effects may be additive if used with alcohol or psychoactive drugs. Avoid hazardous tasks if CNS symptoms (e.g., dizziness, impaired concentration, drowsiness) occur.
• Seek immediate medical evaluation if severe psychiatric adverse events occur.
• Contact physician promptly if rash occurs.
• Watch for early warning signs of liver inflammation or failure (e.g., fatigue, weakness, lack of appetite, nausea/vomiting) as well as later signs (e.g., jaundice, confusion, abdominal swelling, discolored feces); consult your health care professional without delay if such symptoms occur.
• Patients of childbearing potential:
• Use effective contraception (as well as a barrier method) during therapy and for 12 weeks after the last dose.
• Contact your health care provider if you plan to become pregnant, become pregnant, or if pregnancy is suspected during therapy.

Frequently asked questions

• What is the difference between HIV treatments Symfi and Symfi Lo?
• What drugs are contained in the HIV treatment Symfi Lo?

See also:

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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