Drug Levels and Effects:

Summary of Use during Lactation:

Little published information is available on the use of duloxetine during breastfeeding; however, the dose in milk is low and serum levels were low in two breastfed infants. An alternate drug that has been better studied may be preferred, especially while nursing a newborn or preterm infant. If duloxetine is required by the mother, it is not a reason to discontinue breastfeeding. Monitor the infant for drowsiness, adequate weight gain, and developmental milestones, especially in younger, exclusively breastfed infants and when using combinations of psychotropic drugs.

Drug Levels:

Maternal Levels.

Six lactating women who were at least 12 weeks postpartum and weaning their infants were given duloxetine 40 mg with food every 12 hours for 3.5 days. Milk samples from both breasts were obtained before and at 1, 2, 3, 6, 9 and 12 hours after the dose on day 4. Peak milk duloxetine levels occurred at an average of 6 hours after the dose. The amount of duloxetine excreted into breastmilk was approximately 7.4 mcg (range 3.6 to 15 mcg) daily in these women. The normalized milk excretion corresponded to an infant dosage of 0.2 mcg/kg/day or 0.14% (maximum 0. 0.25%) of the weight-adjusted maternal dosage. The excretion of duloxetine metabolites, which are inactive, into breastmilk was not studied.[1]

A woman took oral extended-release duloxetine 60 mg daily (868 mcg/kg/day) during pregnancy and breastfeeding. On day 32 postpartum, milk samples were obtained 10 minutes and 6 hours after the dose. The first (trough) sample contained 31 mcg/L of duloxetine and the second (peak) sample contained 64 mcg/L. The authors calculated that an exclusively breastfed infant would receive a dose of 7.1 mcg/kg daily at this maternal dosage, corresponding to 0.82% of the weight-adjusted maternal dosage.[2]

A woman with recurrent depression took duloxetine 60 mg daily throughout pregnancy and breastfeeding. At 18 days postpartum, the mother collected milk samples before the daily dose and at 8 more times during the next 22.5 hours. The peak milk concentration occurred at about 7 hours after the dose. The average milk concentration over the 24-hour dosage interval was 51 mcg/L. Hindmilk concentrations were somewhat higher than foremilk concentrations at the 2 times when they were measured separately. The authors estimated that the infant received a duloxetine dose of 0.81% of the mothers weight-adjusted dose via breastmilk.[3]

Infant Levels.

An infant whose mother was taking oral extended-release duloxetine 60 mg daily was exclusively breastfed. On day 32 of life, a blood sample was obtained 4 hours after the last nursing which was 8 hours and 15 minutes after the mother's previous dose. Duloxetine was undetectable (<1 mcg/L) in the infant's plasma.[2]

An infant was breastfed (extent not stated) by a mother taking duloxetine 60 mg daily. At 18 days of age, the infant's plasma concentration was 0.82% that of the mother's plasma level at 7.6 hours after the mother's dose.[3]

Effects in Breastfed Infants:

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

Possible Effects on Lactation:

In a small prospective study, 8 primiparous women who were taking a serotonin reuptake inhibitor (SRI; 3 takingfluoxetineand 1 each taking citalopram, duloxetine, escitalopram, paroxetine or sertraline) were compared to 423 mothers who were not taking an SRI. Mothers taking an SRI had an onset of milk secretory activation (lactogenesis II) that was delayed by an average of 16.7 hours compared to controls (85.8 hours postpartum in the SRI-treated mothers and 69.1 h in the untreated mothers), which doubled the risk of delayed feeding behavior compared to the untreated group. However, the delay in lactogenesis II may not be clinically important, since there was no statistically significant difference between the groups in the percentage of mothers experiencing feeding difficulties after day 4 postpartum.[4]

After one nonpregnant woman began taking duloxetine, her serum prolactin increased and previous galactorrhea, which had decreased after stopping venlafaxine, increased again. After stopping duloxetine, her prolactin decreased to normal and galactorrhea ceased.[5]

A woman who was taking duloxetine at an unspecified dose for depression reported a milky discharge from her nipples. She had not experienced this effect with previous antidepressant therapy. Her serum prolactin was elevated, and an MRI of her head found no tumors. Duloxetine was stopped and she was treated with escitalopram 20 mg daily and cabergoline 0.5 mg twice weekly for one month. At this time her serum prolactin was normal and the galactorrhea had stopped.[6]

In a study of cases of hyperprolactinemia and its symptoms (e.g., gynecomastia) reported to a French pharmacovigilance center, duloxetine was not found to have an increased risk of causing hyperprolactinemia compared to other drugs.[7]

Alternate Drugs to Consider:



1. Lobo ED, Loghin C, Knadler MP et al. Pharmacokinetics of duloxetine in breast milk and plasma of healthy postpartum women. Clin Pharmacokinet. 2008;47:103-9. PMID:18193916
2. Briggs GG, Ambrose PJ, Ilett KF et al. Use of duloxetine in pregnancy and lactation. Ann Pharmacother. 2009;43:1898-902. PMID:19809008
3. Boyce PM, Hackett LP, Ilett KF. Duloxetine transfer across the placenta during pregnancy and into milk during lactation. Arch Womens Ment Health. 2011;14:169-72. PMID:21359876
4. Marshall AM, Nommsen-Rivers LA, Hernandez LL et al. Serotonin transport and metabolism in the mammary gland modulates secretory activation and involution. J Clin Endocrinol Metab. 2010;95:837-46. PMID:19965920
5. Ashton AK , Longdon MC. Hyperprolactinemia and galactorrhea induced by serotonin and norepinephrine reuptake inhibiting antidepressants. Am J Psychiatry. 2007;164:1121-2. PMID:17606668
6. Korkmaz S, Kuloglu M, Isik U et al. Galactorrhea during duloxetine treatment: a case report. Turk Psikiyatri Derg. 2011;22:200-1. PMID:21870310
7. Trenque T, Herlem E, Auriche P, Drame M. Serotonin reuptake inhibitors and hyperprolactinaemia: a case/non-case study in the French pharmacovigilance database. Drug Saf. 2011;34:1161-6. PMID:22077504

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Antidepressive Agents

  • Antidepressants

  • Adrenergic Uptake Inhibitors

  • Serotonin Uptake Inhibitors

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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