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(Date of issue: February 2014, Version: 2)

This is a UKTIS monograph for use by health care professionals. For case-specific advice please contact UKTIS on 0344 892 0909. To report an exposure please download and complete a pregnancy reporting form. Please encourage all women to complete an online reporting form.

A corresponding patient information leaflet on piperazine use in pregnancy is available at


Piperazine is an anthelmintic used in the treatment of the intestinal nematodes Ascaris lumbricoides (roundworm) and Enterobius vermicularis (pinworm or threadworm).  Piperazine acts to cause flaccid muscle paralysis of the parasite allowing its expulsion.

Data on the use of piperazine in pregnancy is limited but does not indicate an increased risk of congenital malformations or other adverse pregnancy outcome.  Threadworm infestation in pregnancy should, if possible, be eradicated by rigorous attention to hygiene.  If hygiene measures are ineffective in controlling pinworm/threadworm infestation then piperazine +/- sennosides may be used in pregnancy if clinically indicated.

Exposure to piperazine at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy or any additional fetal monitoring.  However, other risk factors may be present in individual cases which may independently increase the risk of adverse pregnancy outcome.  Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.

This product is no longer commercially available in the UK, therefore this document will not be updated.  If up-to-date information is required please contact UKTIS on 0844 892 0909.

This document is regularly reviewed and updated. Only use full UKTIS monographs downloaded directly from to be sure you are using the most up-to-date version. The summaries of these monographs are openly available on

This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to health care professionals at

If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.

If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.

Disclaimer: Every effort has been made to ensure that this monograph was accurate and up-to-date at the time of writing, however it cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes of the measures recommended. The final decision regarding which treatment is used for an individual patient remains the clinical responsibility of the prescriber. This material may be freely reproduced for education and not for profit purposes within the UK National Health Service, however no linking to this website or reproduction by or for commercial organisations is permitted without the express written permission of this service. This document is regularly reviewed and updated. Only use UKTIS monographs downloaded directly from or to ensure you are using the most up-to-date version.