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Drugs and Lactation Database (LactMed®) [Internet]. Bethesda (MD): National Institute of Child Health and Human Development; 2006-.

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Drugs and Lactation Database (LactMed®) [Internet].

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Last Revision: January 15, 2024.

Estimated reading time: 3 minutes

CASRN: 846-49-1

image 134979720 in the ncbi pubchem database

Drug Levels and Effects

Summary of Use during Lactation

Lorazepam has low levels in breastmilk, a short half-life relative to many other benzodiazepines, and is safely administered directly to infants. Evidence from nursing mothers indicates that lorazepam does not cause any adverse effects in breastfed infants with usual maternal dosages. A safety scoring system finds lorazepam possible to use during breastfeeding.[1] Monitor the infant for sedation, poor feeding and poor weight gain.

Drug Levels

Maternal Levels. Four women were given 3.5 mg of lorazepam orally 2 hours before undergoing cesarean section. Colostrum levels of lorazepam averaged 8.5 mcg/L at 4 hours after the dose; conjugated lorazepam metabolites were not measured.[2]

Another woman taking lorazepam 2.5 mg orally twice a day for the first 5 days postpartum had milk levels of free and conjugated lorazepam of 12 and 35 mcg/L, respectively, at an unspecified time on day 5.[3] Since infants can deconjugate and absorb glucuronides, the total drug level is probably more important than the free drug alone. Using the total amount excreted, an exclusively breastfed infant would receive about 7 mcg/kg daily with this maternal dosage or about 8.5% of the maternal weight-adjusted dosage.

A woman who was 4 weeks postpartum was taking lorazepam 2.5 mg 1 to 3 times daily and lormetazepam, which is partially metabolized to lorazepam, 2 mg once daily. On day 5 of therapy after taking 2 doses of lorazepam in the previous 8 hours, her lorazepam milk level was 123 mcg/L. On day 6 after having taken 3 doses in the previous 24 hours, her milk lorazepam level was 89 mcg/L. On day 7, milk levels were 55 and 40 mcg/L at 14 and 18.5 hours after her last dose, respectively.[4]

Three women who were taking oral lorazepam 0.5 mg daily donated milk samples between 3 and 6 days postpartum at 2 hours after a dose at the estimated peak serum concentration and just before a dose. One woman who was taking a dose of 1 mg daily had a 2-hour milk level of 1.64 mcg/L and a trough milk level of 0.826 mcg/L. The other 2 women 2-hour milk levels of 1.72 and 1.98 mcg/L. Both had trough milk levels less than the lower limit of quantification of 0.5 mcg/L.[5]

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

Effects in Breastfed Infants

The newborn infant of a mother taking 2.5 mg of lorazepam orally twice daily for 5 days after delivery showed no signs of sedation.[3]

In a telephone follow-up study, 124 mothers who took a benzodiazepine while nursing reported whether their infants had any signs of sedation. Sixty-four mothers took lorazepam while breastfeeding and none reported sedation in her infant.[6]

A prospective cohort study of infants breastfed by mothers in an inpatient mother-baby psychiatric unit in India followed 7 infants who were exposed to risperidone in breastmilk; most received partial supplementation. One infant whose mother was taking risperidone 4 mg and lorazepam 2 mg developed sedation that resolved when lorazepam was discontinued.[7]

Effects on Lactation and Breastmilk

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

Alternate Drugs to Consider

Oxazepam, Temazepam


Uguz F. A new safety scoring system for the use of psychotropic drugs during lactation. Am J Ther 2021;28:e118-e126. [PubMed: 30601177]
Summerfield RJ, Nielsen MS. Excretion of lorazepam into breast milk. Br J Anaesth 1985;57:1042-3. [PubMed: 4041315]
Whitelaw AG, Cummings AJ, McFadyen IR. Effect of maternal lorazepam on the neonate. Br Med J (Clin Res Ed) 1981;282:1106-8. [PMC free article: PMC1505046] [PubMed: 6113019]
Lemmer P, Schneider S, Muhe A, Wennig R. Quantification of lorazepam and lormetazepam in human breast milk using GC-MS in the negative chemical ionization mode. J Anal Toxicol 2007;31:224-6. [PubMed: 17555647]
Nishimura A, Furugen A, Umazume T, et al. Benzodiazepine concentrations in the breast milk and plasma of nursing mothers: Estimation of relative infant dose. Breastfeed Med 2021;16:424-31. [PubMed: 33449825]
Kelly LE, Poon S, Madadi P, Koren G. Neonatal benzodiazepines exposure during breastfeeding. J Pediatr 2012;161:448-51. [PubMed: 22504099]
Sinha SK, Thomas Kishore M, Thippeswamy H, et al. Adverse effects and short-term developmental outcomes of infants exposed to atypical antipsychotics during breastfeeding. Indian J Psychiatry 2021;63:52-7. [PMC free article: PMC8106424] [PubMed: 34083820]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


Milk, Human

Hypnotics and Sedatives

Anti-Anxiety Agents


Disclaimer: Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.

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Attribution Statement: LactMed is a registered trademark of the U.S. Department of Health and Human Services.

Bookshelf ID: NBK501231PMID: 30000290


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