Generic Name

Saquinavir Mesylate

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Classification

FDA Approved Indications

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

Mechanism of Action

Saquinavir inhibits the HIV-1 protease enzyme, preventing cleavage of the Gag-Pol polyprotein, resulting in the production of immature, non-infectious viral particles.

Dosage and Administration

Adult: Typically 1000 mg twice daily in combination with ritonavir and other antiretrovirals, adjusted based on response and tolerability.

Pediatric: Not generally recommended for pediatric use due to limited data.

Geriatric: Use with caution; adjust dose based on renal and hepatic function.

Renal Impairment: Adjust dose accordingly, as renal impairment has minimal direct effect but may alter pharmacokinetics.

Hepatic Impairment: Use with caution; liver function should be closely monitored, dose adjustments may be necessary.

Pharmacokinetics

Absorption: Poorly absorbed orally; bioavailability increased when taken with food.

Distribution: Widely distributed in body tissues; extensive binding to plasma proteins.

Metabolism: Metabolized mainly by hepatic cytochrome P450 enzymes, primarily CYP3A4.

Excretion: Primarily eliminated via feces; minimal urinary excretion.

Half Life: Approximately 12 hours.

Contraindications

• hypersensitivity to saquinavir or any component of the formulation

Precautions

• Use with caution in patients with hepatic impairment, pre-existing cardiac conditions, or arrhythmias; monitor cardiac function periodically.

Adverse Reactions - Common

• Nausea (Common)
• Diarrhea (Common)
• Fatigue (Common)

Adverse Reactions - Serious

• Prolonged QT interval or Torsade de Pointes (Uncommon; monitor with EKG)
• Hyperglycemia or new onset Diabetes Mellitus (Rare)
• Hepatotoxicity (Rare; monitor liver function tests)

Drug-Drug Interactions

• Coadministration with ritonavir enhances saquinavir levels; use caution.
• Other CYP3A4 inhibitors or inducers can affect saquinavir concentrations.

Drug-Food Interactions

• High-fat meals increase absorption, which may affect plasma levels.

Drug-Herb Interactions

• St. John’s Wort induces CYP3A4 and can reduce saquinavir levels.

Nursing Implications

Patient/Family Teaching

• Take medication exactly as prescribed.
• Report symptoms of arrhythmia, hepatotoxicity, or hypersensitivity.
• Avoid alcohol, St. John’s Wort, and certain herbal supplements.
• Use barrier precautions to prevent HIV transmission.

Special Considerations

Black Box Warnings:

• Potential for serious cardiac arrhythmias due to QT prolongation and Torsade de Pointes.
• Hepatotoxicity has been reported; monitor liver function.

Genetic Factors: Genetic polymorphisms affecting CYP3A4 may influence drug levels.

Lab Test Interference: May cause false elevation in serum amylase and lipase levels.

Overdose Management

Signs/Symptoms: Nausea, vomiting, hypotension, dizziness, or arrhythmias.

Treatment: Supportive care; no specific antidote. Consider activated charcoal if ingestion is recent; ECG monitoring for cardiac effects.

Storage and Handling

Storage: Store at 20-25°C (68-77°F), protected from moisture.

Stability: Stable under recommended storage conditions for the duration of the shelf life.