Treatment of Graves’ hyperthyroidism with thionamides: a position paper on indications and safety in pregnancy

  • M. TonaccheraEmail author
  • L. Chiovato
  • L. Bartalena
  • A. F. Cavaliere
  • P. Vitti
Consensus Statement



Graves’ disease affects 3% of women and 0.5% of men in the general population. The first line treatment of Graves’ hyperthyroidism is based on the administration of antithyroid drugs (ATD), propylthiouracil (PTU), methimazole (MMI) and carbimazole. A recent warning from the Italian Drug Agency (Agenzia Italiana del Farmaco AIFA) reported the risk of MMI-induced acute pancreatitis. In addition, AIFA highlighted the possible association of MMI treatment during the first trimester of pregnancy with congenital malformations, thus recommending the use of effective contraceptive methods in women of childbearing age treated with MMI.

Methods and results

Revision of literature reported less than ten cases of the alleged MMI pancreatitis, allowing the inclusion of MMI in class III drug regarding the relative risk for drug-induced pancreatitis. Data available on the effect of hyperthyroidism per se on the risk of fetal malformations, although scanty, are sufficient to recommend treatment with ATD of the hyperthyroid pregnant woman. Case reports and population studies either suggesting or not suggesting MMI-induced fetal malformations do not allow unquestionable conclusions on this matter.


This consensus by experts from Italian Endocrine and Gynecologic Scientific Societies has edited recommendations derived form the available data and published guidelines of International Scientific Societies.


Pregnancy Embryopathy Methimazole Propylthiouracil Graves’ diseases Pancreatitis 


Compliance with ethical standards

Conflict of interest

On behalf of all authors, the corresponding author states that there is no conflict of interest.

Ethical approval

This article does not contain any studies with human participants or animals performed by any of the authors.

Informed consent

No informed consent.


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Copyright information

© Italian Society of Endocrinology (SIE) 2019

Authors and Affiliations

  • M. Tonacchera
    • 1
    Email author
  • L. Chiovato
    • 2
  • L. Bartalena
    • 3
  • A. F. Cavaliere
    • 4
  • P. Vitti
    • 5
  1. 1.Department of Clinical and Experimental Medicine, Endocrinology UnitUniversity of Pisa, For Associazione Italiana della Tiroide (AIT)PisaItaly
  2. 2.Istituti Clinici Scientifici Maugeri IRCCS and Department of Internal Medicine and TherapeuticsUniversity of Pavia for Associazione Italiana della Tiroide (AIT)PaviaItaly
  3. 3.Department of Medicine and SurgeryUniversity of Insubria, Varese for Associazione Italiana della Tiroide (AIT)VareseItaly
  4. 4.Fondazione Policlinico Universitario A. GemelliIRCCS Roma for Società Italiana di Ginecologia e Ostetricia (SIGO)RomeItaly
  5. 5.Department of Clinical and Experimental Medicine, Endocrinology UnitUniversity of Pisa, For Società Italiana Endocrinologia (SIE)PisaItaly

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