When to stop Carbimazole

[Gillivy-56]

Hi my daughter is currently taking 20 mg Carbimazole for post partum hyperthyroidism. She has been on this since mid November 2024. Her daughter is 10 months old. Her T4 has dropped from 95 to within normal range although T3 and TSH are still abnormal. She has recently noticed increasing fatigue and wonders if she is moving into the hypothyroid state. Should she stop the Carbimazole straightaway as she isn't having bloods done for a few days.

[PurpleNails Administrator]

Welcome to forum.

20mg carbimazole is a moderate starting dose but long term it’s quite a high level.

What have her results been like?

Have doctors been testing 6 weekly? And adjusting dose by FT4 & FT3.

TSH can remain low for a long time after hyper & is not reliable.

what thyroid antibodies have been tested?

Hyper can be transient. Antibodies help check if the issue is autoimmune.

The dose might need reducing / or it may need to be stopped, most with confirmed Graves remain on carbimazole 18 months plus.

[SlowDragon Administrator]

was Graves’ disease confirmed by testing TSI or Trab antibodies

She also needs TPO and TG antibodies tested and vitamin D, folate, ferritin and B12 levels tested

Test early morning for highest TSH

TSH can remain suppressed for weeks or months after Ft4 and Ft3 drop

Always test Ft4 and Ft3