Generic Name

Darunavir

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Classification

FDA Approved Indications

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

Mechanism of Action

Darunavir inhibits the HIV-1 protease enzyme, preventing the cleavage of precursor polypeptides into mature, functional proteins, thereby inhibiting viral replication.

Dosage and Administration

Adult: 600 mg twice daily with food or 800 mg once daily with food in combination with other antiretrovirals.

Pediatric: Not approved for use in children under 3 years old.

Geriatric: No specific dosage adjustment needed; evaluate renal and hepatic function.

Renal Impairment: No dose adjustment necessary for mild to moderate impairment; caution in severe impairment.

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

Pharmacokinetics

Absorption: Complete absorption when taken with food.

Distribution: Widely distributed in body tissues; highly protein-bound (~95%).

Metabolism: Primarily metabolized by CYP3A enzymes in the liver.

Excretion: Metabolites excreted mainly via feces; minor urinary excretion.

Half Life: Approximately 15 hours.

Contraindications

• Hypersensitivity to darunavir or any component of the formulation.

Precautions

• Use with caution in patients with liver impairment, especially hepatitis B or C co-infection.
• Assess for hypersensitivity reactions.

Adverse Reactions - Common

• Rash (Common)
• Nausea (Common)
• Diarrhea (Common)
• Headache (Common)

Adverse Reactions - Serious

• Severe skin reactions (e.g., Stevens-Johnson syndrome) (Rare)
• Hepatotoxicity (Uncommon)
• Clostridioides difficile-associated diarrhea (Uncommon)

Drug-Drug Interactions

• Ritonavir, which is used as a booster.
• Other drugs that are CYP3A inducers or inhibitors.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Take medication with food to enhance absorption.
• Do not alter dose or frequency without consulting a healthcare provider.
• Report any rash, jaundice, or severe side effects immediately.
• Maintain adherence to prevent resistance.

Special Considerations

Black Box Warnings:

• Potential for serious skin reactions and hepatotoxicity.

Genetic Factors: HLA-B*57:01 testing not specifically required for darunavir but important for abacavir.

Lab Test Interference: May cause changes in liver function tests.

Overdose Management

Signs/Symptoms: Nausea, dizziness, hypotension.

Treatment: Supportive care; no specific antidote exists. Dialysis unlikely to be effective due to high protein binding.

Storage and Handling

Storage: Store at room temperature (15-30°C).

Stability: Stable under recommended storage conditions.