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Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-.

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Drugs and Lactation Database (LactMed) [Internet].

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Last Revision: June 21, 2021.

Estimated reading time: 2 minutes

CASRN: 848-75-9

image 134979887 in the ncbi pubchem database

Drug Levels and Effects

Summary of Use during Lactation

Lormetazepam is not approved for marketing in the United States by the U.S. Food and Drug Administration. Lormetazepam has low levels in breastmilk and a short half-life relative to many other benzodiazepines. Limited evidence from nursing mothers indicates that lorazepam does not cause any adverse effects in breastfed infants with usual maternal dosages. No special precautions are required.

Drug Levels

Maternal Levels. Five women who were 2 to 3 days postpartum took 2 mg of lormetazepam daily at 8 pm for 10 days. Milk samples were taken just before the dose and 12 hours later. Lormetazepam milk levels were mostly undetectable (<0.2 mcg/L). The authors estimated that a fully breastfed infant would receive about 300 ng daily of lormetazepam plus its glucuronide metabolite. This amount equates to about 0.35% of the maternal dose.[1]

A woman who was 4 weeks postpartum was taking lormetazepam 2 mg once daily at 10 pm as well as lorazepam 2.5 mg 1 to 3 times daily. On day 5 at 4 pm, after 4 doses of lormetazepam, her milk lormetazepam level was 5.3 mcg/L. She did not take lormetazepam on days 5 or 6. On day 6 at 8 am her milk lormetazepam level was 1.7 mcg/L, and on day 7 it was undetectable (<0.016 mcg/L) at 10 am and 2:30 pm.[2]

Infant Levels. Five women who were 2 to 3 days postpartum took 2 mg of lormetazepam daily at 8 pm for 10 days and fully breastfed their infants. Blood samples were taken at 1.5, 5.5 and 9.5 days after the mothers first dose of lormetazepam. No free lormetazepam was detectable in the plasma of any of the infants. Average lormetazepam glucuronide levels in infant plasma were 0.6 mcg/L on day 1.5, 0.45 mcg/L on day 5.5, and 0.3 mcg/L on day 10.[1]

Effects in Breastfed Infants

Five women who were 2 to 3 days postpartum took 2 mg of lormetazepam daily at 8 pm for 10 days and fully breastfed their infants. The authors of the study noted no pharmacological or adverse effects in any of the infants during the study.[1]

Alternate Drugs to Consider

Lorazepam, Midazolam, Oxazepam


Hümpel M, Stoppelli I, Milia S, et al. Pharmacokinetics and biotransformation of the new benzodiazepine, lormetazepam, in man. III. Repeated administration and transfer to neonates via breast milk. Eur J Clin Pharmacol. 1982;21:421–5. [PubMed: 6122580]
Lemmer P, Schneider S, Muhe A, et al. 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]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


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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