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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: February 15, 2021.

Estimated reading time: 2 minutes

CASRN: 53772-83-1

image 135030361 in the ncbi pubchem database

Drug Levels and Effects

Summary of Use during Lactation

Zuclopenthixol is not approved for marketing in the United States, by the U.S. Food and Drug Administration, but is available in other countries. Limited information indicates that maternal oral doses of up to 50 mg daily or depot injections of 72 mg every 2 weeks produce low levels in breastmilk and no detectable short-term adverse effects in the breastfed infants. No long-term data are available. One international guideline recommends that women taking zuclopenthixol not breastfeed.[1] However, a safety scoring system finds zuclopenthixol possible to use cautiously during breastfeeding.[2] Until more data are available, zuclopenthixol should be used with careful infant monitoring during breastfeeding.

Drug Levels

Maternal Levels. Six women received zuclopenthixol during nursing. Five of the women were receiving the drug orally and one was receiving a depot injection. Oral dosages ranged from 4 to 50 mg daily of zuclopenthixol and the depot decanoate injection dosage was 72 mg every 2 weeks. Milk samples were obtained in the morning before the first oral dose of the day. Milk zuclopenthixol concentrations for 5 of the patients were between 1 and 2 mcg/L. The patient receiving the high oral dose of 50 mg daily had a breastmilk zuclopenthixol level of about 9 mcg/L.[3]

One woman received zuclopenthixol for depression beginning 2 weeks postpartum. She initially received a dose of 24 mg daily (4 mg in the morning and 20 mg at night), but the dose was reduced to 14 mg daily (4 mg in the morning and 10 mg at night) after 4 days. Seven milk samples in total were obtained on days 2, 3, 6, and 8 of therapy. The average of the milk level with the 24 mg daily dosage was 20 mcg/L and with the 14 mg daily dosage it was 5 mcg/L. The authors estimated that an exclusively breastfed infant would receive 0.8 to 3 mcg/kg daily with the maternal doses given or 0.3 to 0.8% of the maternal weight-adjusted dosage.[4]

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

Effects in Breastfed Infants

Six women received zuclopenthixol during nursing. Five of the women were receiving 4 to 50 mg daily by mouth and one was receiving a depot injection of 72 mg every 2 weeks. Their breastfed infants ranged in age from 3 days to 10 months old, 5 of whom were 2 months or under. No immediate adverse effects such infant drowsiness were noted.[3]

Effects on Lactation and Breastmilk

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

Alternate Drugs to Consider

Haloperidol, Olanzapine, Risperidone


Hasan A, Falkai P, Wobrock T, et al. World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for Biological Treatment of Schizophrenia. Part 3: Update 2015 management of special circumstances: Depression, suicidality, substance use disorders and pregnancy and lactation. World J Biol Psychiatry. 2015;16:142–70. [PubMed: 25822804]
Uguz F. A new safety scoring system for the use of psychotropic drugs during lactation. Am J Ther. 2021;28:e118–e26. [PubMed: 30601177]
Aaes-Jørgensen T, Bjørndal F, Bartels U. Zuclopenthixol levels in serum and breast milk. Psychopharmacology (Berl). 1986;90:417–8. [PubMed: 2878463]
Matheson I, Skjaeraasen J. Milk concentrations of flupenthixol, nortriptyline and zuclopenthixol and between-breast differences in two patients. Eur J Clin Pharmacol. 1988;35:217–20. [PubMed: 3191943]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


Antipsychotic Agents

Dopamine Antagonists

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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