Pegvisomant

FDA label

Read the full label on DailyMed ↗

Titration Adjust by 5 mg increments/decrements every 4–6 weeks based on serum IGF-1 (measure q4–6 wk); do not adjust on GH levels or symptoms

Renal Undefined

Hepatic Baseline LTs >3× ULN: do not initiate until comprehensive workup establishes cause (r/o cholelithiasis, esp. after somatostatin analogs)

Instructions

• Obtain baseline ALT, AST, total bilirubin, alkaline phosphatase before first dose; monitor per label schedule (monthly ×6 mo if normal baseline)
• Reconstitute with supplied diluent against vial wall; swirl slowly — do not shake or invert (protein denaturation); use immediately; solution must be clear
• Inject SC into upper arm, upper thigh, abdomen, or buttocks at 90°; rotate site daily to prevent lipohypertrophy
• Serum GH assays read falsely elevated on therapy — do not use GH to guide dosing

Available strengths

• inj 10, 15, 20, 25, 30 mg

Cautions

• Hypoglycemia in diabetes mellitus (GH lowering improves glucose tolerance) — monitor glucose, reduce anti-diabetic drugs as needed
• Liver toxicity — discontinue immediately if LTs ≥5× ULN, or ≥3× ULN with any bilirubin rise; weekly LTs for elevations 3–5× ULN
• Cross-reactivity with GH assays — measured GH appears falsely elevated
• Lipohypertrophy — rotate injection sites daily
• Systemic hypersensitivity (anaphylaxis, laryngospasm, angioedema) — close monitoring if re-initiating

Adverse reactions

• Infection (23% at 10 mg)
• Pain
• Nausea
• Diarrhea
• Abnormal liver tests
• Flu syndrome
• Injection site reaction
• Transaminase elevations (occasionally >10× ULN)
• Postmarketing: anaphylaxis, angioedema, urticaria

Pregnancy Insufficient human data; rabbit post-implantation loss at 6× MRHD (BSA); acromegaly itself may improve during pregnancy; normalized IGF-1 may improve fertility — advise on unintended pregnancy

Lactation Case report: pegvisomant below detection level in human milk; infant effects unknown — weigh benefit vs maternal need