Why do side effects occur with Levothyroxine?

Question

Hello doctor,

Levothyroxine and Armour Thyroid both cause awful side effects for me. What can be done now? I cannot tolerate either of them.

Answer 1

Hi,

Welcome to icliniq.com.

If you are taking treatment for hypothyroidism, it is to see that you get the right dose. But whether you are being over replaced or under replaced should be determined by periodic thyroid function test, if a single hormone, then TSH which shows amplified suppression and elevation of both T4 and T3 in hyper and hypothyroidism (here I presume, as you are being replaced, you initially were diagnosed as primary hypothyroidism, which is the most prevalent thyroid disorder). Serum TSH (thyroid-stimulating hormone from the pituitary) should be done four to six weeks to adjust the dose till the appropriate treatment dose has been settled (TSH normal for a few follow ups at a particular dose), and then, every six months to one year.

Manufactured proprietary Levothyroxine tablets are more comfortable to change the dose with since they have exact dosage preparations, 25, 50, 100 or 150 micrograms, and they and they have only Levothyroxine (T4), no rapidly acting T3. So, sudden alteration of biology is unlikely. The dose has to be adjusted by 25 to 50 micrograms each time. Carefully, half of that change for adjustment in heart disease and the elderly. Some essential clues (better confirm by TSH):under replacement (hypothyroidism)- Weight gain, coarse and dry skin, slow heart rate, constipation. Over replacement (hyperthyroidism)- Weight loss, sweaty warm skin, palpitations, fast heart rate (tachyarrhythmia AF and sometimes heart failure), hyper defecation (increased number of stools) and sometimes diarrhea.

You did tell your age. If you are approaching menopausal age you may experience similar symptoms due to estrogen deficiency but though worth paying attention, it is less likely because your symptoms are related to taking medicine.