Efavirenz

Indications

Efavirenz is used for: HIV infection

Adult Dose

Oral HIV infection Adult: Combined with other antiretrovirals: 600 mg once daily. Dosing at bedtime recommended during 1st 2-4 wk of therapy to improve tolerability. Hepatic impairment Mild (Child-Pugh Class A): Dose adjustment not necessary; use caution Moderate-to-severe (Child Pugh Class B or C): Not recommended

Child Dose

Oral HIV infection Child: Combined with other antiretrovirals: >3 yr, 10-14 kg: 200 mg; 15-19 kg: 250 mg; 20-24 kg: 300 mg; 25-32.4 kg: 350 mg; 32.5-39 kg: 400 mg; >40 kg: 600 mg. To be taken once daily.

Renal Dose

Renal impairment: No dosage adjustment needed

Administration

Should be taken on an empty stomach. Take on an empty stomach, preferably at bedtime.

Contra Indications

Severe hepatic impairment; hypersensitivity; lactation.

Precautions

Mild to moderate liver disease; renal impairment. Monitor liver enzymes and cholesterol. Discontinue if severe skin rash or fever develops; known or suspected hepatitis B or infection. History of mental illness or seizures; elderly. Pregnancy. Children. Lactation: It is not known whether efavirenz is excreted in milk. It should not be administered to nursing mothers. The CDC advises HIV-infected women not to breast-feed to avoid postnatal transmission of HIV.

Pregnancy-Lactation

Pregnancy Category: D Lactation: Unknown if distributed in human milk; the CDC advises HIV-infected women not to breastfeed to avoid postnatal transmission of HIV

Interactions

Hormonal contraceptives; antibacterial e.g. rifampicin, rifabutin, clarithromycin; enzyme inducers. St. John's wort may decrease serum level. Ethanol (hepatic and CNS adverse effects). Potentially Fatal: Life-threatening adverse effects when used with terfenadine, astemizole, cisapride, midazolam, triazolam and ergot alkaloids.

Adverse Effects

Side effects of Efavirenz : >10% Total cholesterol increased (20-40%), Diarrhea (3-14%, children up to 39%), HDL increased (25-35%), Dizziness (28.1%), Rash (5-26%), Fever (children 21%), Depression (19%), Insomnia (16.3%), Cough (children 16%), Vomiting (3-12%), Anxiety (2-13%), Nausea (2-12%) 1-10% Neutropenia (2-10%), Pruitis (9%), Impaired concentration (8.3%), Transaminases increased (2-8%), Somnolence (7.0%), Abnormal dreams (6.2%), Amylase increased (6%), Hyperglycemia (2-5%), Dyspepsia (4%), Abdominal pain (2-3%), Anorexia (2%), Hallucinations (1.2%)

Mechanism of Action

Efavirenz, a non-nucleoside reverse transcriptase inhibitor with activity against HIV, blocks the RNA-dependent and DNA-dependent polymerase activities including HIV replication.