Pharmacologic class: Growth hormone (GH) receptor antagonist
Therapeutic class: GH analog
Pregnancy risk category B
Selectively binds to GH receptors on cell surfaces, where it blocks binding of endogenous GH and interferes with GH signal transduction. This action decreases blood levels of insulin-like growth factor-1 (IGF-1) and other GH-responsive serum proteins.
Solution: 10-mg, 15-mg, and 20-mg vials
Indications and dosages
Adults: Initial subcutaneous loading dose of 40 mg, followed by 10 mg/day subcutaneously. May adjust in 5-mg increments after serum IGF-1 measurement q 4 to 6 weeks; don't exceed maximum daily maintenance dosage of 30 mg.
• Hypersensitivity to drug, its components, or latex (in vial stopper)
Use cautiously in:
• GH-excreting tumors, diabetes mellitus, hepatic dysfunction
• pregnant or breastfeeding patients
• Reconstitute in vial with 1 ml of sterile water for injection.
• Roll vial gently between palms to mix; don't shake. Withdraw prescribed dosage and administer subcutaneously.
CNS: dizziness, paresthesia
CV: chest pain, hypertension, peripheral edema
GI: nausea, diarrhea, abdominal pain
Musculoskeletal: back pain
Other: infection, pain, injection site reaction, accidental injury, flulike symptoms, lipohypertrophy
Drug-drug. Insulin, oral hypoglycemics: decreased insulin sensitivity, reduced requirements for these drugs
Opioids: increased pegvisomant requirement
Drug-diagnostic tests. GH assays: interference with GH measurement
Liver function tests: abnormal results
Drug-behaviors. Opioid addiction: increased pegvisomant requirement
• Assess liver function tests; watch for signs and symptoms of hepatic dysfunction.
• Monitor serum IGF-1 level. If appropriate, discuss dosage adjustments with prescriber.
• Monitor vital signs; check for hypertension, chest pain, and peripheral edema.
• Measure temperature. Watch for signs and symptoms of infection, especially sinusitis or flulike symptoms.
• Assess blood glucose level closely in diabetic patient. Notify prescriber of significant decrease.
• Teach patient proper technique for reconstituting and administering drug subcutaneously.
☞ Instruct patient to immediately report chest pain, peripheral edema, or signs or symptoms of infection.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects him.
• Teach diabetic patient to monitor blood glucose level closely and report significant decrease.
☞ Instruct patient to report yellowing of skin or eyes and other signs and symptoms of hepatic dysfunction. Tell him he'll undergo frequent liver function tests.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs, tests, and behaviors mentioned above.
Pharmacologic: growth hormones
Time/action profile (effects on IGF-1)
|Subcut||within 2 wk||4–6 wk||unknown|
Adverse Reactions/Side Effects
- peripheral edema
- ↑ LFTs
- back pain
- growth hormone deficiency
- ↑ glucose tolerance
Drug-Drug interactionPatients receiving opioid analgesics often require ↑ doses of pegvisomant to normalize IGF-1.
- Assess patient for signs and symptoms of acromegaly (ring size, soft-tissue swelling, arthralgia, headache, perspiration, fatigue) periodically during therapy.
- Monitor patient for signs and symptoms or hepatitis or other liver injury (jaundice, bilirubinemia, fatigue, nausea, vomiting, right upper quadrant pain, ascites, unexplained edema, easy bruising). If these occur, immediately perform a comprehensive hepatic work-up; may require discontinuation.
- Lab Test Considerations: Monitor serum IGF-1 levels 4–6 wk after therapy is initiated or any dose adjustments are made and at least every 6 mo after IGF-1 levels have normalized. Levels should be maintained within the age-adjusted normal range.
- Monitor serum glucose carefully in patients with insulin-dependent diabetes; may increase glucose tolerance causing hypoglycemia, requiring decrease in dose of antidiabetic medications.
- Measure liver tests (serum ALT, AST, total bilirubin and alkaline phosphatase levels) at baseline. If normal—Monitor liver tests monthly during first 6 mo of treatment, quarterly for next 6 mo, and biannually for the next year. If liver tests are elevated, but ≤3 times the upper limit of normal—Monitor liver tests monthly for at least 1 year after initiation of therapy and biannually for the next year. If >3 times the upper limit of normal—Do not treat with pegvisomant until a comprehensive workup establishes the cause of liver dysfunction. If pegvisomant is used, monitor liver tests very closely.
- If patient develops liver test elevations or other signs or symptoms of liver dysfunction during therapy, monitor as follows: If ≥3 but <5 times the upper limit of normal, without signs or symptoms of hepatitis or other liver injury, or ↑ in serum total bilirubin—May continue therapy, but monitor liver tests weekly and perform a comprehensive work-up to determine if alternative cause of liver dysfunction is present. If liver tests are >5 times the upper limit of normal or AST and ALT are >3 times the upper limit of normal associated with any ↑ in total bilirubin—Discontinue pegvisomant immediately, perform a comprehensive work-up, including serial liver tests. If liver tests normalize, therapy may be cautiously reinstated with frequent monitoring of liver tests.
- Do not use serum GH levels to adjust dose. Pegvisomant interferes with the measurement of serum GH concentrations by commercially available assays and may cause an increase in levels.
Potential Nursing DiagnosesDelayed growth and development (Indications)
- Administer loading dose under supervision of health care professional.
- To reconstitute, withdraw 1 mL of sterile water from diluent provided and inject into vial aiming stream at sides of vial. Gently roll vial between hands to dissolve powder. Do not shake; may cause denaturation of medication. Discard vial containing remaining diluent. After reconstitution each vial contains 10, 15, or 20 mg of pegvisomant/mL. Solution should be clear; do not administer solutions that are discolored, cloudy or contain a participate. Administer only 1 dose/vial. Store in refrigerator prior to reconstitution; let warm to room temperature for 10 min prior to administration. Reconstituted solution is stable for 6 hr at room temperature; administer within 6 hr of reconstitution.
- Subcutaneous: Administer with a 27- or 30-gauge needle at a 90° angle in the upper arm, upper thigh, abdomen, or buttocks. Rotate sites each day; do not inject into an area that has a rash, broken skin, or is bruised or lumpy. Do not massage area following injection.
- Instruct patient on the correct technique for administering pegvisomant. Review patient information sheet, preparation of dose, administration sites and technique, and disposal of equipment into a puncture-resistant container. Inform patient that further questions may be answered by their health care professional or by calling (800)-645-1280.
- Instruct patient that missed doses should be omitted; return to schedule the next day. Do not inject a double dose to make up for a forgotten injection.
- Instruct patient to inform their health care professional if they have diabetes or liver problems, or if they take opioid medications.
- May cause dizziness. Caution patient to avoid driving or other activities requiring alertness until effect of the drug is known.
- Advise patient to consult health care professional before taking other Rx or OTC medications, or herbal products.
- Instruct patient to notify health care professional promptly if skin or whites of the eyes turn yellow (jaundice), urine turn dark, stools turn light in color, decreased appetite, nausea, unexplained tiredness, or abdominal pain occur.
- Advise patient to notify health care professional if pregnancy is planned or suspected or if breastfeeding.
- Emphasize the need for frequent lab test to adjust dose and monitor for adverse effects.
- Maintenance of serum IGF-1 concentration within the age-adjusted normal range.
- Control of the signs and symptoms of acromegaly.