Dichloralphenazone

Drug Levels and Effects:




Summary of Use during Lactation:


Short-term or occasional use of dichloralphenazone during breastfeeding is unlikely to adversely affect the breastfed infant, especially if the infant is older than 2 months. Because the active metabolite, trichloroethanol, has a long half-life, long-term use of repeated doses during breastfeeding could result in infant sedation, especially while nursing a neonate or preterm infant. The low doses of dichloralphenazone found in combination migraine products (e.g., Midrin) are less likely to cause drowsiness in the infant unless doses are repeated several times daily. Theantipyrinecomponent of dichloralphenazone is considered unlikely to harm the infant.[1][2] Monitor the infant for excessive drowsiness during use.


Drug Levels:


Dichloralphenazone is a chemical combination of chloral hydrate (64%) andantipyrine(36%).

Maternal Levels.

After 1.3 grams of dichloralphenazone (equivalent to about 830 mg of chloral hydrate) daily in a woman who was 5 month postpartum, milk trichloroethanol levels were found to range from 1.3 to 3.2 mg/L.[3]

Antipyrinewas given to 7 lactating women were 2 to 19 months postpartum. Each woman drank a single oral dose of 18 mg/kg ofantipyrinein solution. Peak milk levels usually occurred 10 minutes after ingestion and ranged from about 10 to 30 mg/L. Theantipyrinehalf-life in milk averaged 11.6 hours (range 5.7 to 21.7 hours). The authors estimated that a fully breastfed infant would ingest 6.4 mg ofantipyrineafter this maternal dose or 0.59% of the maternal dose (not weight-adjusted). Two of the women who were studied before and after pregnancy indicated thatantipyrineclearance might be increased by about two-fold during lactation.[1] The time course ofantipyrineappearance in milk is probably slower than above from dichloralphenazone in a tablet formulation.

Infant Levels.

After a 1.3 gram maternal dose of dichloralphenazone (equivalent to about 1 gram of chloral hydrate), trichloroethanol was detected in her 5-month-old breastfed infant's plasma 21 hours later.[3]


Effects in Breastfed Infants:


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.[3]


Possible Effects on Lactation:


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


References:


1. Berlin CM Jr, Vesell S.Antipyrinedisposition in milk and saliva of lactating women. Clin Pharmacol Ther. 1982;31:38-44. PMID:7053302
2. Reed CB. A study of the conditions that require removal of the child from the breast. Surg Gynecol Obstet. 1908;6:514-27.
3. Lacey JH. Dichloralphenazone and breast milk. Br Med J. 1971;4:684. Letter. PMID:5134581



Substance Identification:




Substance Name:

Dichloralphenazone

CAS Registry Number:

480-30-8

Drug Class:


  • Anti-Inflammatory Agents, Non-Steroidal

  • Hypnotics and Sedatives


  • Administrative Information:




    LactMed Record Number:


    438


    Last Revision Date:


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