Bremelanotide should be used with caution during breastfeeding due to a lack of safety data

The use of medications during breastfeeding presents a significant clinical challenge. Clinicians and mothers must weigh the benefits of treatment against potential risks to the infant. For new drugs, there is often a substantial gap in clinical data regarding their safety during lactation. Bremelanotide, a cyclic heptapeptide melanocortin receptor agonist used for hypoactive sexual desire disorder in premenopausal women, falls into this category. Its safety profile for a breastfed infant is unknown. Understanding the physicochemical properties of a drug, like its molecular weight and structure, can help predict its potential to pass into breast milk and be absorbed by the infant, but this theoretical assessment is no substitute for clinical evidence.

This paper is a review and risk assessment based on the known physicochemical properties of bremelanotide. The authors analyzed the peptide's molecular characteristics to theorize its behavior during lactation. Key properties considered were its structure as a cyclic peptide and its molecular weight of 1025 daltons. The analysis did not involve new experimental or clinical data collection but rather synthesized existing pharmacological information to provide a preliminary safety recommendation in the absence of direct evidence. The primary endpoint of this assessment was to establish a preliminary guideline for the clinical use of bremelanotide in breastfeeding mothers.

The analysis concluded that there is no available clinical information on the use of bremelanotide during breastfeeding. However, theoretical assessment based on its molecular properties suggests a low likelihood of infant exposure. As a cyclic peptide with a relatively large molecular weight of 1025 daltons, the amount of bremelanotide that would pass into breast milk is expected to be very low. Furthermore, even if small amounts were present in the milk, the peptide is likely to be destroyed by digestive enzymes in the infant's gastrointestinal tract, preventing significant systemic absorption. This protein degradation is a common fate for orally ingested peptides, which typically have poor bioavailability.

Because bremelanotide is a cyclic peptide molecule with a molecular weight of 1025, the amount in milk is likely to be very low and absorption is unlikely because it is probably destroyed in the infant's gastrointestinal tract. Despite this favorable theoretical profile, the authors stress that this prediction is not a substitute for clinical data. The complete absence of studies means that potential effects on the infant cannot be definitively ruled out.

Written by TitrateLab, separately from the study summarized above.