Nurses Compass
Drug Guide
Saquinavir
Classification
Therapeutic: Antiretroviral agent, HIV protease inhibitor
Pharmacological: 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, which results in the production of immature, non-infectious viral particles.
Dosage and Administration
Adult: Typically 1000 mg twice daily in combination with ritonavir to boost levels.
Pediatric: Limited data; use under specialist guidance.
Geriatric: Adjust dose based on tolerance and response; caution with concomitant medications.
Renal Impairment: No specific dose adjustment necessary; monitor renal function.
Hepatic Impairment: Use with caution; dose adjustment may be necessary due to metabolism by liver enzymes.
Pharmacokinetics
Absorption: Well absorbed orally, but bioavailability is increased when administered with ritonavir.
Distribution: Widely distributed; high protein binding (~98%).
Metabolism: Primarily hepatic via CYP3A4 enzyme.
Excretion: Metabolites excreted primarily in feces; minimal renal excretion.
Half Life: Approximately 7 hours when boosted with ritonavir.
Contraindications
- Hypersensitivity to saquinavir or other components.
- Concomitant use with certain drugs (see drug interactions).
Precautions
- Patients with underlying cardiac conditions, since saquinavir may prolong QT interval and cause significant QTc prolongation or PR interval prolongation. Use with caution in patients with hepatic impairment or underlying heart disease. Monitor for signs of metabolic disturbances, such as hyperlipidemia and diabetes.
Adverse Reactions - Common
- Nausea (Common)
- Diarrhea (Common)
- Rash (Common)
Adverse Reactions - Serious
- Prolongation of QT interval and PR interval, potentially leading to arrhythmias (Less common)
- Hepatotoxicity, including elevations in liver enzymes (Less common)
- Lactic acidosis (Rare)
Drug-Drug Interactions
- Several medications metabolized by CYP3A4, including certain statins, benzodiazepines, ergot alkaloids, and antiarrhythmics.
- Ritonavir (used to boost saquinavir levels)
- Other QT-prolonging drugs.
Drug-Food Interactions
- High-fat meals may reduce bioavailability; administer on an empty stomach or as directed.
Drug-Herb Interactions
N/ANursing Implications
Assessment: Monitor for drug interactions, cardiac status (ECG), hepatic function, and metabolic parameters.
Diagnoses:
- Risk for cardiac arrhythmias due to QT prolongation.
- Imbalanced nutrition: less than body requirements due to gastrointestinal side effects.
Implementation: Administer as prescribed, preferably with ritonavir to boost levels. Monitor ECG periodically. Check liver function tests regularly.
Evaluation: Assess viral load and CD4 count to evaluate treatment efficacy. Monitor for adverse effects and interactions.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report any signs of arrhythmia (palpitations, dizziness, syncope).
- Avoid concurrent use of other QT-prolonging drugs.
- Attend regular follow-up appointments for blood work and ECGs.
- Notify healthcare provider before starting any new medications.
Special Considerations
Black Box Warnings:
- Potential for serious drug interactions leading to life-threatening arrhythmias.
- Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases.
Genetic Factors: Genetic variations in CYP3A4 may affect drug levels.
Lab Test Interference: May cause transient elevations in liver enzymes and lipid levels.
Overdose Management
Signs/Symptoms: Nausea, vomiting, hypotension, dizziness.
Treatment: Supportive care; no specific antidote. Monitor cardiac status and provide symptomatic treatment.
Storage and Handling
Storage: Store at room temperature (20-25°C), protected from moisture and light.
Stability: Stable for the duration of the shelf life as indicated by manufacturer.