USE OF MONTELUKAST IN PREGNANCY

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(Date of issue: August 2015, Version: 2.1)

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 montelukast use in pregnancy is available at www.medicinesinpregnancy.org.

Summary

Montelukast is a cysteinyl leukotriene type-1 receptor antagonist licensed as an anti-asthmatic medication for patients inadequately controlled by inhaled corticosteroids or short-acting beta-agonists, and for asthmatics with exercise-induced bronchoconstriction.

Although the available data are limited both by lack of power and/or formal statistical analysis in some studies, there is currently no good evidence that montelukast exposure during pregnancy increases the overall risk of congenital malformation, spontaneous abortion, intrauterine death, decreased fetal growth or premature delivery above that observed in women prescribed other asthma medications. A possible association between montelukast exposure and limb reduction defects was identified from spontaneous reports provided to the manufacturer of montelukast, although other studies have failed to support this finding.

Uncontrolled maternal asthma has been associated with a number of adverse pregnancy outcomes including fetal loss, preterm birth and low birth weight, as well as adverse maternal events such as preeclampsia. Where clinically indicated, continued maternal treatment with montelukast in pregnancy is likely to far outweigh any theoretical risk posed to the fetus. Montelukast therapy should not be discontinued on account of pregnancy without careful consideration of the risk to both mother and fetus of uncontrolled maternal asthma.

Exposure to montelukast at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy. 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 document is regularly reviewed and updated. Only use UKTIS monographs downloaded directly from TOXBASE.org or UKTIS.org to be sure you are using the most up-to-date version.

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 www.toxbase.org.

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 TOXBASE.org or UKTIS.org to ensure you are using the most up-to-date version.