U.S. flag

An official website of the United States government

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

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

Cover of Drugs and Lactation Database (LactMed)

Drugs and Lactation Database (LactMed) [Internet].

Show details

Ethyl Loflazepate

Last Revision: April 18, 2022.

Estimated reading time: 2 minutes

CASRN: 29177-84-2

image 388554262 in the ncbi pubchem database

Drug Levels and Effects

Summary of Use during Lactation

Ethyl loflazepate is not approved for marketing in the United States by the U.S. Food and Drug Administration. Available data indicate that the infant dose from milk might be rather high. An alternate drug with more published data and lower milk levels is preferred, especially while nursing a newborn or preterm infant.

Drug Levels

Ethyl loflazepate is immediately and completely metabolized to an unstable metabolite after intestinal absorption, then it is metabolized to the active metabolite, norfludiazepam (CM7116).

Maternal Levels. Two women who were taking ethyl loflazepate orally donated milk samples between 3 and 6 days postpartum at 1 hour after a dose at the estimated peak serum concentration and just before a dose. one woman who was taking a dose of 0.5 mg daily had a 1-hour milk level of norfludiazepam of 6.55 mcg/l and a trough milk level of 8.1 mcg/L. The other woman was taking a dose of 1 mg daily. she had a 1-hour milk level of norfludiazepam of 13.6 mcg/l and a trough milk level of 11.4 mcg/L. The authors estimated that the estimated relative infant dose of ethyl loflazepate would be 12.4 to 12.9%.[1]

At one day postpartum, a mother began ethyl loflazepate 1 mg daily, sertraline 50 mg daily and continued alprazolam 0.4 mg daily. Two breastmilk samples on day 3 postpartum contained 7.8 and 10.6 mcg/L of norfludiazepam. The sample that contained 7.8 mcg/L was taken at 22.6 hours after the dose. Two samples on day 4 postpartum contained 8.7 and 9.1 mcg/L and one sample on day 6 postpartum contained 13.4 mcg/L, which was taken at 0.5 hours after the dose. Using the highest measured milk level of 13.4 mcg/L, the estimated dose of norfludiazepam would be 2 mcg/kg daily. This translates to 2.5 mcg/kg daily of ethyl loflazepate, which is 13.7% of the weight-adjusted maternal dosage of ethyl loflazepate.[2]

Infant Levels. A mother who was partially nursing her infant (daily milk intake 80 to 200 mL of pumped breastmilk and 100 to 200 mL of formula) was taking ethyl loflazepate 1 mg daily. The cord blood level of norfludiazepam on the day of delivery was 53.1 mcg/L and on day 5 postpartum, the infant had a serum concentration of 32.1 mcg/L of norfludiazepam.[2]

Effects in Breastfed Infants

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

Effects on Lactation and Breastmilk

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

Alternate Drugs to Consider

Lorazepam, Midazolam, Oxazepam


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]
Saito J, Tachibana Y, Wada YS, et al. Transfer of ethyl loflazepate into cord blood, breast milk, and infant's serum: A case report. J Clin Psychopharmacol. 2022 [PubMed: 35343929]

Substance Identification

Substance Name

Ethyl Loflazepate

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.


Related information

Similar articles in PubMed

  • Review Flurazepam[Drugs and Lactation Database (...]
    Review Flurazepam
    . Drugs and Lactation Database (LactMed). 2006
  • Review Clotiazepam[Drugs and Lactation Database (...]
    Review Clotiazepam
    . Drugs and Lactation Database (LactMed). 2006
  • Review Quazepam[Drugs and Lactation Database (...]
    Review Quazepam
    . Drugs and Lactation Database (LactMed). 2006
  • Review Etizolam[Drugs and Lactation Database (...]
    Review Etizolam
    . Drugs and Lactation Database (LactMed). 2006
  • Review Flunitrazepam[Drugs and Lactation Database (...]
    Review Flunitrazepam
    . Drugs and Lactation Database (LactMed). 2006
See reviews...See all...

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...