Hi,
Thyronorm 25 mcg tablet is a synthetic version of thyroxine, a hormone that is naturally produced in your body. Thyronorm is used to treat an underactive thyroid gland or 
hypothyroidism. It helps replace the hormone which is not being produced by the thyroid gland in sufficient quantities and helps regulate energy and metabolism in your body. Common side effects of Thyronorm are vomiting, anxiety, flushing, weight loss, nervousness, 
restlessness, palpitations etc.
Thyronorm can stimulate the breakdown of glycogen and glycogenic amino acids into glucose. Under hypoxic conditions, lactate production causes pain in muscle. But, about 50% of patients with hypothyroidism can complain of 
muscle cramps, 
muscle weakness, joint pain, back pain etc. So, do repeat 
thyroid function tests of your patients and adjust the Thyronorm according to the test results. 
Take care. Hope I have answered your question. Let me know if I can assist you further. 
Regards,
Dr. Zubayer Alam, General And Family Physician