Diabetes Centre. Treatment for Overactive Thyroid Gland. Information

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1 Diabetes Centre Treatment for Overactive Thyroid Gland Information

2 Your doctor will have told you that you have an overactive thyroid. We hope the following information will help you to understand the possible reasons for this and the treatment you may receive. What is the thyroid gland? The thyroid gland is situated in the neck and produces thyroid hormones which are released into the blood stream. The amount of thyroid hormone in the blood controls the rate at which the body ticks over. Too much thyroid hormone causes the body rate to be set too fast, causing a fast heart rate, sweating, increased appetite, weight loss, nervousness and irritability. If the thyroid is under active the body slows up, causing weight gain, slowness, constipation and a tendency to feel the cold. The thyroid hormones are made from iodine, which is concentrated in the thyroid gland. The rate at which the thyroid hormones are released into the blood stream is controlled by a gland in the brain called the pituitary gland. 2

3 Overactive thyroid (Thyrotoxicosis) This is a condition which occurs more commonly in women and may run in families. It is usually treated with tablets initially although a different and more permanent form of treatment may be recommended later. The condition is not difficult to treat but if left untreated, it can cause a strain to be put on the heart and may lead to osteoporosis. Tablet treatment is usually continued for up to 12 months. After this time the condition may return to normal on its own and the tablets can be stopped. There is always a risk that the condition may return and you will need regular blood tests to check that your thyroid is working normally. If the overactive thyroid persists after several months of treatment you may be advised to have a more permanent form of treatment (radioiodine or surgery). If you are taking anti-thyroid drugs, usually carbimazole or propylthiouracil, these should be stopped one week before the radioactive iodine is given. 3

4 Instructions for patients receiving radioiodine Normally the treatment is given on a Tuesday in the Department of Nuclear Medicine at Northampton General Hospital. For one week prior to treatment please avoid eating fish or other seafood since seafood is rich in natural iodine which will compete with the radioactive iodine for space in the thyroid gland which makes the treatment less effective. Tablets for the management of an overactive thyroid 1. Carbimazole This acts on the thyroid gland to reduce the amount of thyroid hormones (thyroxine [T4]) and triiodothyronine [T3] being made. It usually takes 2 to 3 weeks to become fully effective. Tablets can be taken as a single daily dose. There are 2 sizes of tablet: 5mg and 20mg. It is usual to start with 20-40mg daily and then reduce the dose progressively until you are taking a small daily maintenance dose (usually 5-10mg). Alternatively the large dose of 40mg of carbimazole may be continued for 12 to 18 months to block the thyroid. In this case you would also receive Thyroxine mcg to take over the work of the thyroid gland. This is usually referred to as block replacement treatment. You will need 4

5 regular blood tests to check that the dose of tablets is correct. 2. Propylthiouracil (PTU) PTU acts in a very similar way to carbimazole. It is equally effective and has much the same side effects, although it is not used as much because it needs to be taken in divided doses. Less PTU passes across the placenta and enters breast milk & so it tends to be preferred in women who become pregnant. 3. B-Blockers (i.e. propranolol, atenolol) These are used to control the symptoms of an overactive thyroid and sometimes diagnosed along with either carbimazole or PTU PTU. Side Effects of Carbimazole and Propylthiouracil Most people are able to take these tablets without any problems. However some may develop side effects. These may be severe enough to lead to the tablets being stopped but they will get better. The usual side effects are: Skin Rash General aches & pains in the muscles and joints 5

6 Other people notice changes, which are not really side effects of the tablet but are the result of the condition getting better. These include a tendency to weight gain (people with untreated thyrotoxicosis lose weight because they burn up calories) and a feeling of slowing up. Very rarely these drugs may cause a much more serious side effect: bone marrow suppression (which reduces the number of white cells in the blood). Although rare, it is very serious because it can trigger severe infection. It is not related to the dose or the length of time a person takes the tablets. If you have any of the following symptoms, stop your tablets, call your GP and ask him / her to check your blood count. Symptoms which might suggest bone marrow suppression are: Severe flu-like symptoms Bad sore throat Bad mouth ulcers Bruising 6

7 Radioiodine and Surgery for an Overactive Thyroid If your thyroid remains overactive after a few months on tablets you may be advised to have a more permanent form of treatment. There are 2 possible treatments available: radioiodine or surgery and your doctor will discuss these with you. Contact Information For further advice or information, please contact: The secretary to the Consultant Diabetologist & Endocrinologist The Diabetes Centre Kettering General Hospital Rothwell Road Northants NN16 8UZ

8 If you need this information in another format or language, please telephone Further information about the Trust is available on the following websites: KGH - NHS Choices - Ref: PI.787 December 2012 Review: September 2014