Zepbound (Tirzepatide) Use During Breastfeeding
Zepbound (tirzepatide) should be avoided during breastfeeding due to complete absence of safety data regarding its excretion into breast milk and effects on breastfed infants.
Evidence-Based Rationale
Lack of Safety Data
- There are no published studies examining tirzepatide concentrations in human breast milk or its effects on breastfed infants 1, 2, 3
- The clinical trials evaluating tirzepatide efficacy and safety specifically excluded breastfeeding women from participation 1
- Current literature on tirzepatide focuses exclusively on glycemic control and weight management outcomes in non-lactating populations 2, 3
Drug Characteristics Relevant to Lactation
- Tirzepatide is a large peptide molecule (dual GLP-1/GIP receptor agonist) administered subcutaneously 2
- While large molecular weight peptides typically have limited transfer into breast milk (similar to other biologics), this cannot be assumed without specific lactation studies 4
- The drug has a prolonged half-life allowing once-weekly dosing, which could theoretically result in accumulation if any transfer occurs 2
Clinical Decision Framework
When Tirzepatide Treatment is Essential:
- Discontinue breastfeeding if tirzepatide therapy cannot be delayed or substituted 3
- Consider the indication: if used for type 2 diabetes, alternative medications with established breastfeeding safety profiles exist (such as insulin or metformin) 4
- If used for obesity management, weight loss interventions should generally be deferred during lactation given the lack of urgent medical necessity
Important Caveats:
- The absence of evidence is not evidence of safety - the precautionary principle applies when no lactation data exists 4
- Unlike medications with decades of post-marketing surveillance showing safety in lactation (such as warfarin or heparin), tirzepatide is a recently approved agent with no real-world lactation experience 4, 2
- The manufacturer's prescribing information explicitly notes the lack of data on tirzepatide presence in human milk and effects on milk production 3