Carbimazole

Carbimazole is a thiourea antithyroid drug that acts by blocking the production of thyroid hormones. It is entirely metabolized to methimazole, equivalent to 60% of the drug. It is used in the treatment of hyperthyroidism, the preparation of hyperthyroid patients for thyroidectomy, as an adjunct to radioactive iodine therapy, and in the treatment of thyroid crisis. It is administered orally at an initial dose of 15 to 40 mg per day, in a single or divided doses; occasionally, it may be necessary to administer up to 60 mg per day.

It is excreted in breast milk in clinically insignificant amounts ^{(Fumarola 2011, Rylance 1987, Low 1979, Johansen 1972)}. Plasma levels in breastfed infants were very low. ^{(Rylance 1987)}

It does not cause alterations in thyroid function or the physical and mental development of infants fed breast milk from treated mothers, so it can be safely administered during breastfeeding. ^{(Azizi 2006, 2003 and 1996, Verd 1998, Lamberg 1984)}

Various medical societies and expert authors consider the use of this medication during breastfeeding to be safe in low or moderate doses not exceeding 30 mg daily or 50 mg weekly. ^{(LactMed 2024, Alexander 2017, Fumarola 2011, Azizi 2011, Karras 2010, Glatstein 2009, Bartalena 2005)}

American Academy of Pediatrics: medication usually compatible with breastfeeding. ^{(AAP 2001)}

See below the information of this related product:

• Methimazole (Safe product and/or breastfeeding is the best option.)