Home Drug Guide Saquinavir Mesylate

Drug Guide

Generic Name

Saquinavir Mesylate

Brand Names Invirase

Classification

Therapeutic: Antiretroviral, Protease Inhibitor

Pharmacological: HIV Protease Inhibitor

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

Assessment: Monitor viral load, CD4 counts, liver function tests, and cardiac status (ECG) during therapy.

Diagnoses:

  • Risk for infection due to HIV progression
  • Risk of cardiovascular complications

Implementation: Administer with food; observe for adherence, adverse effects, and drug interactions.

Evaluation: Assess viral load suppression, CD4 count stability, and adverse effects regularly.

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.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.