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Growth Hormone Receptor Antagonist

Pegvisomant

Brand names: Somavert

Pegvisomant is a pegylated growth hormone receptor antagonist used to treat acromegaly in patients with an inadequate response to surgery, radiotherapy or somatostatin analogues.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It binds to growth hormone receptors and blocks their functional dimerisation, preventing growth hormone signalling and thereby reducing hepatic production of insulin-like growth factor 1 (IGF-1).

Prescribing in practice

  • Hepatic enzymes can rise during treatment, occasionally markedly, so liver function must be monitored and significant or symptomatic derangement investigated.
  • Because it blocks the growth hormone receptor rather than lowering growth hormone, treatment is titrated to IGF-1 rather than growth hormone levels.
  • It does not control tumour size, so pituitary tumour growth should continue to be monitored by imaging.

Monitoring

Monitor serum IGF-1 to guide dosing and check liver function tests regularly throughout treatment.

Counselling the patient

  • Treatment success is judged by IGF-1 blood levels rather than growth hormone.
  • Report jaundice, dark urine or persistent nausea, which may signal liver problems.
  • Rotate injection sites to reduce the risk of fatty lumps developing at the site.

Evidence & guidelines

Normalisation of IGF-1 with pegvisomant in acromegaly is supported by the SPC and pivotal clinical trial data.

Reference: Endocrine Society Acromegaly Guidelines 2014; ACROSTUDY Registry; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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