Is Pegvisomant safe while breastfeeding?

Here is what LactMed, the Drugs and Lactation Database published by the U.S. National Institute of Child Health and Human Development (NICHD), reports about Pegvisomant. The text below is quoted from that source — it is not our own verdict.

Summary of use during breastfeeding

Limited data indicate that pegvisomant is poorly excreted into breastmilk. Because pegvisomant is not orally absorbed, it is unlikely to adversely affect the breastfed infant. Polyethylene glycol is not excreted into breastmilk.[1]

Effects on the breastfed infant

A woman with acromegaly was treated with lanreotide Autogel 120 mg monthly, cabergoline 2 mg weekly and pegvisomant 80 mg weekly. She breastfed (extent not stated) her infant and they were followed for 12 years. Her child had normal growth and development.[3]

Effects on milk supply

A woman with acromegaly was treated with pegvisomant 10 mg postpartum. She successfully breastfed her infant for 4 months.[4]

A woman with acromegaly was treated with lanreotide Autogel 120 mg monthly, cabergoline 2 mg weekly and pegvisomant 80 mg weekly. She breastfed (extent not stated) her infant and they were followed for 12 years.[3]

Levels in milk

Maternal Levels. A woman was being treated during pregnancy for acromegaly with subcutaneous pegvisomant at a dosage that was progressively escalated from 15 mg to 25 mg daily during the course of pregnancy, and presumably postpartum. At an unreported time postpartum, pegvisomant was not detectable (<50 mcg/L) in breastmilk. The patient’s breastmilk growth hormone concentration was 0.6 mcg/L compared to <0.1 mcg/L in 3 breastmilk samples from normal healthy mothers.[2]

Infant Levels. Relevant published information was not found as of the revision date.

Source: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Pegvisomant” (LM607). LactMed on NCBI Bookshelf. LactMed is a registered trademark of the U.S. Department of Health and Human Services.

Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.