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


Last Revision: October 31, 2018.

Estimated reading time: 2 minutes

CASRN: 55268-74-1

Chemical structure

Drug Levels and Effects

Summary of Use during Lactation

Because of the minute levels of praziquantel in breastmilk, amounts ingested by the infant are small and would not be expected to cause any adverse effects in breastfed infants. Expert opinion holds that lactation should not be a contraindication to maternal treatment with praziquantel.[1][2][3] To minimize infant exposure, a single dose can be taken just before the infant's longest sleep period or an alternate method of feeding (e.g., stored milk) can be used for 24 to 36 hours after a single dose or the last of a series of doses.[4]

Drug Levels

Maternal Levels. Five women were given a single oral dose of praziquantel of about 50 mg/kg. The average peak milk level of 440 mcg/L usually occurred 2 hours after the dose, although the peak occurred 6 hours after the dose in 1 individual. By 24 hours after the dose, the drug was undetectable (<4 mcg/L) in 4 women and near the lower limit of detection (6 mcg/L) in the other. The authors calculated that the average amount excreted into milk in 24 hours was 27 mcg (range 6.8 to 75 mcg) which corresponded to 0.0087% of the total (not weight-adjusted) dosage.[5]

The same paper reported another 5 women given three 20 mg/kg oral doses at 4-hour intervals. With this regimen, peaks were observed 4 and 10 hours after the first dose. A meal near the second dose probably delayed its absorption. The peaks were 250 and 460 mcg/L, respectively. The authors calculated that the average amount excreted into milk in 24 hours was 25.6 mcg (range 4.6 to 49 mcg) which corresponded to 0.0007% of the total (not weight-adjusted) dosage.[5]

Data from the above studies were used to create a pharmacokinetic model of praziquantel excretion into milk.[6] The model predicts a half-life of about 1 hour for praziquantel in milk.

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

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.


Olds GR. Administration of praziquantel to pregnant and lactating women. Acta Tropica. 2003;86:185-95. [PubMed: 12745136]
Allen HE, Crompton DW, de Silva N et al. New policies for using anthelmintics in high risk groups. Trends Parasitol. 2002;18:381-2. [PubMed: 12377247]
Friedman JF, Olveda RM, Mirochnick MH et al. Praziquantel for the treatment of schistosomiasis during human pregnancy. Bull World Health Organ . 2018;96:59-65. [PMC free article: PMC5791873] [PubMed: 29403101]
Porto I. Antiparasitic drugs and lactation: focus on anthelmintics, scabicides, and pediculicides. J Hum Lact. 2003;19:421-5. [PubMed: 14620457]
Putter J, Held F. Quantitative studies on the occurrence of praziquantel in milk and plasma of lactating women. Eur J Drug Metab Pharmacokinet. 1979;4:193-8. [PubMed: 575330]
DiLeo MD, Brown RD, Wilson JT. Praziquantel transfer into human breast milk: simultaneous resolution of plasma and breast milk data by nonlinear regression analysis. J Clin Pharmacol. 1988;28:942. Abstract.

Substance Identification

Substance Name


CAS Registry Number


Drug Class

  • Breast Feeding
  • Anti-Infective Agents
  • Anthelmintics
  • Antiparasitic 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 Temazepam[Drugs and Lactation Database (...]
    Review Temazepam
    . Drugs and Lactation Database (LactMed). 2006
  • Review Tolazamide[Drugs and Lactation Database (...]
    Review Tolazamide
    . Drugs and Lactation Database (LactMed). 2006
  • Review Pentoxifylline[Drugs and Lactation Database (...]
    Review Pentoxifylline
    . Drugs and Lactation Database (LactMed). 2006
  • Review Pindolol[Drugs and Lactation Database (...]
    Review Pindolol
    . Drugs and Lactation Database (LactMed). 2006
  • Review Nifedipine[Drugs and Lactation Database (...]
    Review Nifedipine
    . 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...