Generic Name

Efavirenz

---

Classification

FDA Approved Indications

• Treatment of HIV-1 infection in combination with other antiretroviral agents

Mechanism of Action

Efavirenz binds directly to reverse transcriptase enzyme, causing inhibition of viral RNA-dependent DNA polymerase, preventing viral replication.

Dosage and Administration

Adult: 600 mg once daily, taken on an empty stomach at bedtime

Pediatric: Not established for children under 3 years; for older children, dose based on weight and age, under medical supervision

Geriatric: No specific dosage adjustment required but caution advised due to potential for increased adverse effects

Renal Impairment: Use with caution; no specific dosage adjustment recommended but monitor closely

Hepatic Impairment: Use with caution; dose adjustment may be necessary, especially in severe hepatic impairment.

Pharmacokinetics

Absorption: Well absorbed orally, peak plasma levels in 3-5 hours

Distribution: Widely distributed; crosses blood-brain barrier

Metabolism: Extensively metabolized in the liver via CYP2B6 and CYP3A4 enzymes

Excretion: Metabolites excreted in urine and feces

Half Life: Approximately 40-55 hours

Contraindications

• Hypersensitivity to efavirenz or any component of the formulation

Precautions

• Use with caution in patients with mental health disorders, history of suicidal thoughts, or cardiovascular risk factors; potential for hepatotoxicity; pregnant women should consult healthcare providers due to risk of teratogenicity

Adverse Reactions - Common

• Central nervous system effects (dizziness, insomnia, vivid dreams) (Common)
• Rash (Common)
• Gastrointestinal disturbances (Common)

Adverse Reactions - Serious

• Psychosis, severe depression, suicidal ideation (Rare)
• Hepatotoxicity including hepatitis and failure (Rare)

Drug-Drug Interactions

• Rifampin, St. John’s Wort, other hepatically metabolized drugs

Drug-Food Interactions

• High-fat meals may increase absorption, so take consistently with or without food as prescribed

Drug-Herb Interactions

• St. John’s Wort may reduce efavirenz levels

Nursing Implications

Patient/Family Teaching

• Take on an empty stomach at bedtime
• Do not skip doses; adherence is critical
• Report new or worsening mental health symptoms, rash, or jaundice immediately
• Avoid alcohol and concomitant hepatotoxic drugs

Special Considerations

Black Box Warnings:

• Potential for serious psychiatric symptoms and suicidality; for women of childbearing potential, risk of teratogenicity

Genetic Factors: CYP2B6 slow metabolizers may have higher plasma concentrations, increasing risk of toxicity

Lab Test Interference: Can cause false-positive results in some drug tests

Overdose Management

Signs/Symptoms: Dizziness, rash, vomiting, somnolence, ataxia

Treatment: Supportive care; no specific antidote; consider activated charcoal if ingestion is recent; monitor cardiac if overdose severe

Storage and Handling

Storage: Store below 25°C, away from light and moisture

Stability: Stable under recommended storage conditions