Propylthiouracil and Carbimazole are the medications used in the treatment of hyperthyroidism.
Category C status: Based on the mechanism of action & pharmacological activity, suspicion of causing harmful effects to the human fetus/neonate without having safety evidence of causing congenital anomalies. Any effects caused are reversible in nature.
Category D status: Safety evidence from post-marketing experience/spontaneous sources, comprising the suspected causes or increased incidence of fetal malformation which are irreversible in nature.
TGA received post-marketing case reports pertaining to the congenital abnormalities suspected with the use of propylthiouracil and carbimazole which lead to the update of pregnancy category status of these two medicines from C to D. PI documents for these products are updated to reflect this new category of safety information.
Health Authority:
Therapeutic Goods & Administration (TGA) – Health authority of Australia.
Important note for Healthcare professionals:
While prescribing/dispensing/administering minocycline, it is recommended to make patient and patient care providers aware of this risk of potential congenital anomalies with exposure of propylthiouracil and carbimazole in pregnant women.
Individual benefit-risk analysis: Owing to the updated safety information for these anti-thyroid medicines, consider using these medicines in pregnant women only in the context of favorable benefit-risk balance specific to individual pregnant women.
Important note for Public (Patients/patient care providers):
Be aware of the potential congenital malformation associated with the use of these antithyroid medicines and inform your respective doctor or healthcare professional about the plan for pregnancy or suspicion of conception, delayed/missed periods etc., This facilitates the effective assessment of benefit-risk ratio and identification of suitability of these medicine for use in pregnancy period/or looking for alternative medicine with less risk potential for congenital malformation having the favorable benefit risk profile.
Voluntary ADR reporting:
Every medicinal product has both benefits and risks. Medicines are authorized to market based on the favorable benefit-risk profile anticipated at the time of regulatory approval/entry into market. However, the safety profile of medicine would continuously updates owing to safety data from the post marketing experience from public. If the rate of reporting of suspected adverse drug reactions (ADR) from public is line with the actual occurrence of ADRs, the time lapse for taking regulatory action can be reduced and thereby improving patient safety.
All health care professionals and consumers of pharmaceutical medicinal products are encouraged to be aware of this fact and observe/monitor for any possible adverse events, reactions, medication errors, or quality complaints of medicinal products and report the same to your respective national health authority.
This would accumulate safety evidence for medicinal products which in turn help health authorities to take regulatory actions at the earliest possibility for a better patient safety and overall public health.