Methimazole Pregnancy and Breastfeeding Warnings

Methimazole is also known as: Northyx, Tapazole

Methimazole Pregnancy Warnings

Methimazole has been assigned to pregnancy category D by the FDA. Methimazole readily crosses the placental membranes and can induce goiter and cretinism in the developing fetus. In addition, rare instances of congenital defects: aplasia cutitis, as manifested by scalp defects; esophageal atresia with tracheoesophageal fistula; and choanal atresia with absent/hypoplastic nipples, have occurred in infants born to mothers receiving methimazole therapy during pregnancy. The risk is especially high during the first trimester (during organogenesis). The manufacturer recommends using the lowest dose possible if methimazole is used during pregnancy. If the patient becomes pregnant while taking the drug, the patient should be warned of the potential hazard to the fetus. Propylthiouracil is typically the preferred agent in pregnancy as is crosses the placenta to a lesser degree.

Methimazole Breastfeeding Warnings

Methimazole is excreted into human milk. Studies found no adverse effects on nursing infants of mothers taking methimazole, especially if thyroid function is monitored at weekly or biweekly intervals.

See Also...

Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Wolters Kluwer Health and Drugs.com is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This drug information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate that the drug or combination is safe, effective, or appropriate for any given patient. Multum Information Services, Inc. does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. Copyright 2000-2008 Multum Information Services, Inc. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse, or pharmacist.

Hide
(web3)