Nurses Compass
Drug Guide
Pegvisomant
Classification
Therapeutic: Antineoplastic, Growth Hormone Receptor Antagonist
Pharmacological: Biologic, Recombinant DNA Protein
FDA Approved Indications
- Treatment of acromegaly in patients who have failed or are intolerant to other therapies
Mechanism of Action
Pegvisomant is a genetically engineered, pegylated growth hormone (GH) receptor antagonist that blocks the action of GH, thereby decreasing insulin-like growth factor 1 (IGF-1) levels.
Dosage and Administration
Adult: Initial dose: 10 mg subcutaneously once daily. Dose adjustments as needed based on IGF-1 levels, up to 30 mg daily.
Pediatric: Not typically used in pediatric patients.
Geriatric: No specific dosage adjustments, but monitor closely due to potential comorbidities.
Renal Impairment: No specific adjustment; use caution and monitor hepatic function.
Hepatic Impairment: Use with caution; hepatic function should be monitored throughout therapy.
Pharmacokinetics
Absorption: Peak plasma concentrations occur approximately 2-4 hours after subcutaneous injection.
Distribution: Widely distributed with a volume of distribution of approximately 7–10 liters.
Metabolism: Metabolized via proteolytic degradation similar to endogenous proteins.
Excretion: Eliminated primarily through proteolytic degradation; not primarily excreted renally.
Half Life: Approximately 3-6 days depending on dose and patient.
Contraindications
- Hypersensitivity to pegvisomant or excipients.
Precautions
- Hepatic impairment: risk of increased liver enzymes and potential hepatotoxicity. Regular liver function tests are recommended.
- Monitor for signs of hypersensitivity reactions.
- Use with caution in patients with impaired hepatic function.
Adverse Reactions - Common
- Liver enzyme elevations (ALT, AST) (Common)
- Injection site reactions (Common)
- Headache, nausea (Common)
Adverse Reactions - Serious
- Hepatotoxicity (Rare, potentially serious)
- Anaphylaxis, hypersensitivity reactions (Rare)
Drug-Drug Interactions
- Other hepatotoxic drugs
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor liver function tests before treatment and periodically during therapy. Assess for signs of hypersensitivity.
Diagnoses:
- Risk for hepatic injury
- Altered medication efficacy
Implementation: Administer subcutaneously once daily at the same time each day. Educate patient on injection technique.
Evaluation: Regular assessment of IGF-1 levels, liver function tests, and clinical response.
Patient/Family Teaching
- Instruct on proper injection technique.
- Report any symptoms of allergic reactions, jaundice, or severe headache.
- Inform that therapy requires regular blood tests.
- Advise not to stop medication without consulting healthcare provider.
Special Considerations
Black Box Warnings:
- Hepatotoxicity, including liver failure, has been reported. Liver function must be monitored regularly.
Genetic Factors: Not specifically indicated.
Lab Test Interference: May affect liver function tests; interpret with caution.
Overdose Management
Signs/Symptoms: Liver enzyme elevations, hypersensitivity reactions.
Treatment: Discontinue pegvisomant and monitor liver function. Supportive care as needed.
Storage and Handling
Storage: Store refrigerated (36°F to 46°F or 2°C to 8°C). Do not freeze.
Stability: Stable for up to 30 days at room temperature, but refrigeration is preferred.