Amitriptyline Use During Breastfeeding
Amitriptyline can be used during breastfeeding with caution, but requires careful infant monitoring for sedation and poor feeding, as the drug is excreted into breast milk and serious adverse reactions in nursing infants are possible.
FDA Drug Label Guidance
The FDA label explicitly states 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" because of the potential for serious adverse reactions in nursing infants 1. This is the highest-level regulatory guidance available and must frame the clinical decision.
Key pharmacokinetic data from the FDA label 1:
- Amitriptyline is excreted into breast milk
- In one documented case: maternal serum levels were 83-141 ng/mL, breast milk levels were 135-151 ng/mL (similar to or higher than serum)
- Notably, no trace was detected in that infant's serum
Critical Safety Concern: Case Report of Severe Adverse Effects
A 2017 case report documented severe sedation and poor feeding in a breastfed newborn whose mother was taking only 10 mg/day of amitriptyline 2. This is particularly concerning because:
- The dose was very low (typical doses are 25-150 mg/day for depression)
- The adverse effects were severe enough to warrant publication
- This demonstrates that even minimal doses can cause clinically significant infant toxicity
Supporting Evidence for Cautious Use
A 1996 systematic review found that amitriptyline was not detected in quantifiable amounts in nursing infants' serum in most cases, with no adverse effects reported in those studies 3. A 1982 pharmacokinetic study calculated that the infant received approximately 1/100th of the maternal dose, with no detectable drug in infant serum and no clinical signs 4.
However, these older studies conflict with the 2017 case report of severe toxicity 2, suggesting individual variation in infant exposure and metabolism may be substantial.
Clinical Decision Algorithm
If amitriptyline must be used during breastfeeding:
Exhaust alternatives first: Consider other antidepressants with better lactation safety profiles (sertraline and paroxetine are preferred SSRIs with low breast milk levels) 5, 6
Use lowest effective dose: The case of severe toxicity occurred at only 10 mg/day 2, so there is no "safe" low dose
Implement mandatory infant monitoring:
- Watch for excessive drowsiness/sedation
- Monitor feeding quality and frequency
- Assess for decreased alertness
- Consider baseline and follow-up infant serum drug levels if available
Timing strategy: Dose immediately after breastfeeding or before the infant's longest sleep interval to minimize infant exposure 6
Consider pumping and discarding: For peak milk concentrations (30-60 minutes post-dose, similar to alcohol kinetics)
Common Pitfalls to Avoid
- Don't assume low doses are safe: The severe toxicity case occurred at 10 mg/day 2
- Don't rely solely on older literature: The 2017 case report contradicts earlier reassuring data
- Don't forget active metabolites: Nortriptyline is an active metabolite that also transfers to milk 4
- Don't ignore maternal anticholinergic effects: These may impair maternal caregiving ability
Risk-Benefit Context
The FDA's position that this requires a choice between nursing and the drug 1 reflects the genuine uncertainty and documented risk. Given that effective alternatives with better safety profiles exist (sertraline, paroxetine), amitriptyline should generally be avoided during breastfeeding unless there are compelling reasons why alternatives have failed or are contraindicated 5, 6.
If maternal depression is severe and amitriptyline is the only effective option after multiple trials, the benefit to the mother (and thus to the infant through improved maternal mental health) may justify the risk, but only with intensive infant monitoring and informed consent about the documented case of severe toxicity 2.