Can a breastfeeding woman use Contrave (naltrexone-bupropion) or Adipex (phentermine) while nursing?

Contrave and Adipex Use During Breastfeeding

Neither Contrave (naltrexone-bupropion) nor Adipex (phentermine) should be used while breastfeeding due to significant safety concerns and lack of established safety data.

Adipex (Phentermine) - Contraindicated

Phentermine is contraindicated during breastfeeding. The FDA drug label explicitly states that "other amphetamines are present in human milk" and recommends that "a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother" 1.

Key Safety Concerns:

• Amphetamine-related structure: Phentermine is chemically and pharmacologically related to amphetamines, which are known to transfer into breast milk 1
• Stimulant effects on infant: Potential for central nervous system stimulation, irritability, poor sleep patterns, and feeding difficulties in the nursing infant 1
• Cardiovascular risks: Risk of tachycardia, hypertension, and other cardiovascular effects that could theoretically affect the infant 1
• No lactation studies: There are no published studies establishing safety in breastfeeding women 1

Clinical Context:

Phentermine is approved only for short-term weight loss as an adjunct to diet and exercise 1. Weight loss interventions should generally be deferred during lactation given the lack of urgent medical necessity and the established benefits of breastfeeding 2.

Contrave (Naltrexone-Bupropion) - Use with Extreme Caution

Bupropion during breastfeeding requires extreme caution and is generally not recommended. While limited data exists (only 21 documented cases), there are concerning reports of serious adverse events 3.

Critical Safety Data:

• Seizure risk: Two case reports document seizures in breastfed infants exposed to bupropion through breast milk 3
• Drug transfer confirmed: Bupropion is present in human milk and has been detected in infant serum, though typically at very low levels 3
• Limited safety data: Only 21 cases have been documented, which is insufficient to establish safety 3
• Guideline recommendation: The American Journal of Obstetrics and Gynecology guidelines state "caution is advised" for bupropion use during breastfeeding 3

Additional Considerations for Contrave:

• Combination product: Contrave contains both naltrexone and bupropion, compounding the uncertainty
• No specific lactation data: There are no published studies on the naltrexone-bupropion combination during breastfeeding
• Weight loss indication: Like phentermine, this is a non-urgent indication that should be deferred during the breastfeeding period 2

Clinical Decision-Making Algorithm

Step 1: Assess urgency of weight loss

• Weight loss for cosmetic or general health purposes is not urgent and should be deferred until after breastfeeding 2
• If obesity-related comorbidities require immediate intervention, consider alternative approaches

Step 2: Prioritize breastfeeding benefits

• Breastfeeding provides short-term protection against infectious morbidity and mortality, and long-term protection against inflammatory bowel disease, obesity, diabetes, and childhood cancers for the infant 3
• For mothers, breastfeeding reduces risks of diabetes, hypertension, and breast, ovarian, endometrial, and thyroid cancer 3
• International medical societies recommend exclusive breastfeeding for approximately 6 months 3

Step 3: Consider safer alternatives

• Lifestyle modifications: Diet and exercise remain the safest approach during breastfeeding 1
• Delay pharmacotherapy: Wait until after breastfeeding is complete to initiate weight loss medications
• If diabetes management needed: Use insulin or metformin, which have established breastfeeding safety profiles 2

Common Pitfalls to Avoid

• Assuming pregnancy safety equals breastfeeding safety: A drug that is safe during pregnancy may not be safe for the nursing infant 4
• Relying on "probably safe" assumptions: The absence of evidence is not evidence of safety, and the precautionary principle applies 2
• Underestimating infant vulnerability: Premature or compromised infants may be at higher risk for drug accumulation and toxicity 4
• Ignoring timing strategies: Even if a medication were considered, avoiding breastfeeding during peak maternal serum concentrations could theoretically reduce infant exposure 4, though this does not make these specific medications acceptable

Shared Decision-Making Points

When counseling patients, emphasize:

• The documented seizure risk with bupropion exposure through breast milk 3
• The amphetamine-like properties of phentermine and known transfer of amphetamines into breast milk 1
• The substantial benefits of breastfeeding for both mother and infant that outweigh non-urgent weight loss goals 3
• Alternative timing: Weight loss medications can be safely initiated after breastfeeding is complete 2

The choice should involve shared decision-making, but the medical recommendation is clear: discontinue breastfeeding if these medications are deemed essential, or preferably, defer these medications until after breastfeeding is complete 3, 1.