Low TSH and Low T4

I have a TSH of 0.24 and T4 of 1.04.  I have been on Dilantin for 30 years.  I have been on Thyroid replacement therapy for 18 years with monthly injection of B12.  I have had extreme fatigue and chest pains.  Seeing neurologist for medicine change and have be referred to endocrinologist.  How concerned should I be?  What tests should be given?  Is this my pituitary gland?

Thank you for your time in advance

[peggy64]

Inez, hi, I have been on dilantin for about 10 years. Why are you thinking of changing? Is there some kind of interaction or something?

[AR-10]

What thyroid medication are you taking?

Get a TSH, a Free T4, and a Free T3 run, and see where your hormones really are. You may be high on your Free T3.

[InezKelley]

Peggy - I have had trouble with Dilantin since September.  Horrible side effects that progressively got worse.  The I tired going onto the 30 mg kapseals.  Still I don't feel right and I am not going to continue like this; if I can help it.

Thyroid hormones (including levothyroxine): Phenytoin may alter the metabolism of thyroid hormones, reducing its effect; there is limited documentation of this interaction, but monitoring should be considered.

AR-10  I am on 100mcg Levothyroxine sodium.  Thanks for the input...Talk with my doctor on Tuesday!

[dai3symae]

I found this article that has info about meds like dilantin and thyroid. Interesting read...

http://www.emedicine.com/neuro/TOPIC371.HTM