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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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Chloral Hydrate

Last Revision: October 31, 2018.

Estimated reading time: 1 minute

CASRN: 302-17-0

Chemical structure

Drug Levels and Effects

Summary of Use during Lactation

Short-term or occasional use of chloral hydrate during breastfeeding is unlikely to adversely affect the breastfed infant, especially if the infant is older than 2 months. Because the active metabolite of chloral hydrate has a long half-life, other sedative-hypnotics are preferred for long-term use during breastfeeding, especially while nursing a neonate or preterm infant. Monitor the infant for excessive drowsiness.

Drug Levels

Maternal Levels. In a study of 50 women who were given 1.3 grams of chloral hydrate rectally on day 3 postpartum, peak chloral hydrate milk levels of about 10 mg/L occurred within the first hour and fluctuated between 6 and 10 mg/L for 10 hours after the dose. Milk levels of the active metabolite, trichloroethanol, reached a peak of about 40 mg/L 45 minutes after the dose and gradually decreased to about 12 mg/L over the next 23 hours.[1]

After 1.3 grams of dichloralphenazone daily dichloralphenazone (equivalent to about 1 gram of chloral hydrate), milk trichloroethanol levels were found to range from 1.3 to 3.2 mg/L in one woman.[2]

Infant Levels. After a 1.3 gram maternal dose of dichloralphenazone (equivalent to about 1 gram of chloral hydrate), trichloroethanol was detected in the breastfed infant's plasma 21 hours later.[2]

Effects in Breastfed Infants

An old review article states that if an infant is breastfed within 45 minutes of a maternal dose of chloral hydrate while she is taking 1.5 grams twice daily, the infant will fall into a prolonged, restless sleep.[3]

A single maternal rectal dose of 1.3 grams chloral hydrate in 50 women was stated to not adversely affect their breastfed newborn infants.[1]

Minimal morning sedation occurred in a 5-month-old breastfed infant whose mother was taking 1.3 grams of dichloralphenazone (equivalent to about 1 gram of chloral hydrate) every evening plus chlorpromazine 100 mg 3 times daily. The infant's overall development was said to be normal at 3 months of age.[2]

Effects on Lactation and Breastmilk

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

Alternate Drugs to Consider

Zaleplon, Zolpidem


Bernstine JB, Meyer AE, Bernstine RL. Maternal blood and breast milk estimation following the administration of chloral hydrate during the puerperium. J Obstet Gynaecol Br Emp. 1956;63:228-31. [PubMed: 13320217]
Lacey JH. Dichloralphenazone and breast milk. Br Med J. 1971;4:684. Letter. [PMC free article: PMC1799850] [PubMed: 5134581]
Reed CB. A study of the conditions that require removal of the child from the breast. Surg Gynecol Obstet. 1908;6:514-27.

Substance Identification

Substance Name

Chloral Hydrate

CAS Registry Number


Drug Class

  • Breast Feeding
  • Hypnotics and Sedatives

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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