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Question-I would appreciate your help in management of 24 y/o female who is 28 weeks IUP. I have never seen the patient but the perinatologist called for an opinion. Hence, I felt it best to seek your advise.

Patient has Grave’s disease which was treated prior to pregnancy with Tapazole. Then, she was switched to PTU in the first trimester and then switched back to Tapazole in the second trimester. 6 weeks ago, on Tapazole 10 mg TID her FT4 was 2.2. Repeat FT4 – 1.5 weeks ago – was further elevated at 4.4. Endocrinologist increased her Tapazole to 40 mg a day and also started her on Propranolol on advise of cardiologist as she was tachycardic with HR of 108 bpm.

The perinatologist increased her Tapazole to 60 mg per day. 2 or 3 days later, patient came in with HTN, tachycardia – HR 110 bpm, edema, and 2+ proteinuria. Patient is suspected to have pre-eclempsic toxemia. She was started on Labetolol. The endocrinologist refused to see patient saying he was uncomfortable with such high doses of Tapazole.

I recommended the following as patient is admitted to the hospital: (recent TFTs – pending) Switched Tapazole to PTU 100 mg QID with daily monitoring of LFTs, FT4, and FT3
Reduce PTU dose as FT4 returns to normal.
Continue Labetolol and HR control as per cardiology.

Perinatologist is very concerned that PTU may worsen liver dysfunction as patient has pre- eclamsia. Current LFT are normal.
I would like to know if you have any other comments or recommendations.
Also we would like to know what is a maximum safe dose for Methimazole/PTU in pregnancy.
Am I right in switching to PTU because of her severe thyrotoxic state or would you have continued with higher doses of Tapazole?
Would you consider steroids or any other treatment for her hyperthyroidism?
I would appreciate an early response as the perinatologist is quite distressed by this situation.
Thanks as always for your valuable prompt input.  Great regards, Radha Reddy, MD

RESPONSE-Dear Dr Reddy-Apologies for delay but I was away in Scotland. The dose of Tapazole is indeed high but if necessary (and it seems to be necessary here) this dose can be used in pregnancy and even increased. If 100mg qid of PTU is effective I would not alter the dose but more could be given if necessary. While PTU can affect LFTs it is rare. If the hyperthyroidism is not coming under control( ie possibly thyroid storm) then steroids can be used. Plasma exchange has also been used in this situation. Regards, John Lazarus, MD