My 18 Year Old Son Had A Valve Repair Surgery

My 18 year old son had a valve repair surgery 5 months back in June in Bangalore, due to MVP & MR. When he was admitted for the surgery and all the routine blood tests were done, his TSH was found high (7.130). They started Thyronorm 25mcg daily and told to continue it till around 3 1/2 months (100 tablets), then wait for 2 months without medication and then to check the thyroid. So now in Dec when his thyroid was checked the TSH is found to be 10.46. T4 is normal. We have been advised to continue with Thyronorm 25mcg again. Pls advise. My son is 6ft tall and weighs 62 kg. He is also on medication Ramipril 2.5 mg.