Lormetazepam use while Breastfeeding
Medically reviewed by Drugs.com. Last updated on May 1, 2021.
Lormetazepam Levels and Effects while Breastfeeding
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.
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.
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.
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.
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.
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]
CAS Registry Number
Hypnotics and Sedatives
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