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New Study Shows Safe Levels Of Ketamine In Breast Milk

A recently published study The Pharmacokinetics of Ketamine in the Breast Milk of Lactating Women: Quantification of ketamine and metabolites is the first study conducted on this subject providing data that supports the safety of ketamine administration for the treatment of postpartum depression (PPD) and other emotional disorders during breastfeeding.

Full text article and references available here.

Post-Partum depression is a significant issue world-wide and affects up to 15% of mothers, with collateral damage to families. Evidence suggests that this condition is both under-recognized and under-treated. Moreover, treatment is often ineffective and PPD can persist causing long term harm to the patient and their relationships.

Ketamine is in ever widening use for a variety of psychiatric disorders and its potency in improving and eliminating depressive disorders in sub-anesthetic doses has been extensively documented. Much of the expanding clinical use of ketamine has focused on its ability to exert a potent and rapid antidepressant effect in patients with severe treatment resistant depression.


The outcomes of this study have huge implications for future treatment of women with PPD whose current options are limited and pose significant moral dilemmas. Conventional first-line treatment for PPD is the use of SSRIs which are known to have a long list of side-effects.  When it comes to infant exposure to this class of medication through breastmilk, the data is so limited that no conclusions can be made about the long term effects on cognition, behaviour or emotional changes.  A few of the common side effects of SSRIs include: agitation, anxiety, loss of appetite and weight loss, dizziness, blurred vision, headaches and sleeping problems.  It is understandable why so many women choose to forego this option.

In my clinical work with women who are having to make this choice, I see them face an impossible risk vs benefit scenario. Most societal norms instruct women to be “selfless;” they should put their children’s needs before their own. If a new mother chooses to take an SSRI to treat symptoms of a postpartum mood disorder, she may worry she is being selfish. Ultimately, if a woman has significant fear about the risk to her infant, any benefit from the medicine itself may not be sufficient to treat the postpartum mood disorder. And she may fear that if she chooses to medicate, she will have to wean her baby off of breastfeeding—a loss to both.

– Melissa Whippo

If a woman does choose to take SSRIs, these medications can take months before their effect is known and often people need to cycle through more than one medication before finding one that is possibly effective on their depressive symptoms.  The reality is that infants may be exposed to potentially risky levels of SSRIs without any positive effect on the mother’s depression or emotional disorder. However, it is important to note that the decision to forgo, discontinue or start medications should be made between the mother and her healthcare team.


During the Wolfson study, the 4 breastfeeding women received 2 different intramuscular doses of ketamine—0.5mg/kg and 1.0mg/kg during a period of 12 hours where breastfeeding was postponed.  Breast milk was collected at baseline, 3, 6, 9 and 12 hours post ketamine administration.  The amount of ketamine in the women’s breast milk at the 12 hour mark was insignificant.  For the woman who received the highest dose of 76 milligrams of ketamine, only 24 micrograms (0.024 mg) of ketamine was secreted in the 12 hour period.

These findings show only small concentrations of ketamine in breast milk which decline rapidly within hours.  This data supports that women may continue to breastfeed after a brief interruption limited to hours. This offers symptomatic women a new choice for treatment where they can continue breastfeeding, a fundamental aspect of the mother-child nurturing relationship.

The current treatment models of ketamine psychotherapy include infrequent dosing which avoids accumulation of ketamine levels in infants’ plasma levels.


This study represents a huge first step to begin the systematic study of the potential use of ketamine and Ketamine Assisted Psychotherapy for postpartum emotional disorders. It is the hope that with further study an important new method to treat postpartum depression and other postpartum emotional disorders will become available.

The Wolfson team believes ketamine presents great promise for women suffering with postpartum emotional difficulties.