I don't think you should mix the lexapro with saintjohn's wort but I also wanted to pass on this info on safety and breastfeeding--
J Clin Psychiatry. 2006 Feb;67(2):305-9.
St. John's wort (Hypericum perforatum) and breastfeeding: plasma and breast milk concentrations of hyperforin for 5 mothers and 2 infants.
Klier CM, Schmid-Siegel B, Schäfer MR, Lenz G, Saria A, Lee A, Zernig G.
Department of Child and Adolescent Neuropsychiatry, Medical University Vienna,Vienna, Austria, and the Division of Clinical Pharmacology and Toxicology,Hospital for Sick Children, Toronto, Ontario, Canada.email@example.com
BACKGROUND: Herbal preparations for depression, such as St. John's wort, are often preferred over pharmaceutical preparations by mothers and midwives after childbirth because these preparations are available to patients as over-the-counter "natural" treatments and are popularly assumed to be safe. The only existing report on St. John's wort excretion into human milk showed that only 1 active component (hyperforin) was detectable in breast milk, but was not detectable in the infants' plasma. Another report found more cases of minor problems in infants breast-fed by women taking St. John's wort. However, significance was reached only in comparison with disease-matched women (p<.01),not healthy controls (p=.20). METHOD: Five mothers who were taking 300 mg of St. John's wort 3 times daily (LI 160 [Jarsin], Lichtwer Pharma GmbH; Berlin,Germany) and their breastfed infants were assessed. Thirty-six breast milk samples (foremilk and hindmilk collected during an 18-hour period) and 5 mothers'and 2 infants' plasma samples were analyzed for hyperforin levels by tandem mass spectrometry (LC/MS/MS; limit of quantification=0.1 ng/mL). Data were gathered from January 2001 to February 2002. RESULTS: Hyperforin is excreted into breast
milk at low levels. However, the compound was at the limit of quantification in the 2 infants' plasma samples (0.1 ng/mL). Milk/plasma ratios ranged from 0.04 to 0.13. The relative infant doses of 0.9% to 2.5% indicate that infant exposure to hyperforin through milk is comparable to levels reported in most studies assessing anti-depressants or neuroleptics. No side effects were seen in the mothers or infants. CONCLUSION: These results add to the evidence of the relative safety of St. John's wort while breast-feeding found in previous observational studies.
PMID: 16566628 [PubMed - indexed for MEDLINE]
Pharmacopsychiatry. 2002 Jan;35(1):29-30.
St. John's wort (Hypericum perforatum)--is it safe during breastfeeding?
Klier CM, Schäfer MR, Schmid-Siegel B, Lenz G, Mannel M.
Department of Psychiatry, General Hospital, University of Vienna, Währinger
Gürtel 18-20, 1090 Vienna, Austria. firstname.lastname@example.org
Both doctors and patients often treat postnatal depression with herbal
preparations derived from St. John's wort. Because these preparations are
available to patients as "natural" over-the-counter drugs for depression, they
are popularly assumed to be safe. However, no systematic information exists
regarding treatment of postnatal depression, infant's safety or pharmacokinetics of hypericum constituents in human breast milk or infant plasma. A mother with post-natal depression was admitted at our service. Her pharmacist had recommended taking a St. John's wort preparation three times a day (Jarsin 300, Lichtwer Pharma AG, Berlin, Germany). Four breast-milk samples (fore and hind milk) during an 18-hour period were analyzed to measure concentration of hypericin and hyperforin. Only hyperforin is excreted into breast milk at a low level, hyperforin and hypericin (two major active components) were below the lower limit of quantification (BLQ: below lower limit of quantification, LQ hypericin: 0.20
ng/ml, LQ hyperforin: 0.50 ng/ml) in this infant's plasma. No side effects were seen in the mother or infant. Before recommending St John's wort for the treatment of depression to women who breastfeed, long-term studies of outcome in infants are needed.
PMID: 11819157 [PubMed - indexed for MEDLINE]
J Clin Psychiatry. 2003 Aug;64(8):966-8.
The safety of St. John's wort (Hypericum perforatum) during breastfeeding.
Lee A, Minhas R, Matsuda N, Lam M, Ito S.
Division of Clinical Pharmacology and Toxicology, The Hospital for Sick Children, Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada.
BACKGROUND: We examined the safety of St. John's wort to nursing mothers and their infants. METHOD: A prospective, observational, cohort study was conducted. Thirty-three breastfeeding women receiving St. John's wort (Group 1) who contacted our teratogen/toxicant counseling service regarding the safety of St.John's wort during breastfeeding were followed up between May 1999 and April 2001. These women were compared with 101 disease-matched (Group 2) and 33 age-and parity-matched nondisease controls (Group 3). Information collected included maternal and neonatal demographics, breastfeeding duration, use of St. John's wort, maternal and infant adverse events, infant weight over the first year of life, and whether or not the mother experienced a decrease in lactation. RESULTS:
There were no statistically significant differences found in maternal or infant
demographics or maternal adverse events. Whereas only 1 infant each in Groups 2 and 3 was reported to be colicky, there were 2 cases of "colic," 2 of
"drowsiness," and 1 of "lethargy" in Group 1 (p <.01; Group 1 vs. Group 2, p
<.01; Group 1 vs. Group 3, p =.20). Although 3 of these women in Group 1
consulted their doctor, specific medical treatment was not required. No
significant difference was observed in the frequency of maternal report of
decreased milk production among the groups, nor was a difference found in infant weight over the first year of life. CONCLUSION: These results provide a framework for the management of breastfeeding women receiving St. John's wort.
PMID: 12927015 [PubMed - indexed for MEDLINE]
there is further studies as well on how weakly or strongly it effects certain other drugs via the liver