Side effects of antithyroid drugs

Hyperthyroidism medications help block the thyroid hormone's ability to produce when the thyroid gland is overactive. However, you need to see your doctor right away if you develop symptoms such as fever or sore throat while taking hyperthyroid medications.

When a patient has a blood test with high blood thyroxine and low or non-existent thyroid-stimulating hormone (TSH) levels, that person's thyroid gland is overactive. In particular, the level of thyroid-stimulating hormone in the blood is important because it is the hormone that signals the patient's thyroid gland to produce more thyroxine, which becomes a sign of hyperthyroidism.
The doctor will examine and try to detect if the patient's fingers have slight tremors when they are extended, reflexive or overactive, eye changes and moist, warm skin. Also check the patient's thyroid gland for enlarged, bumpy or tender when swallowing and check the patient's pulse for fast, slow or irregular pulse.
When combining the results of clinical and paraclinical examination, the doctor will make a conclusion whether the patient has hyperthyroidism or not. However, in some cases thyroid blood tests can give false results when you are taking biotin, a B vitamin supplement, which can also be found in multivitamins. Therefore, patients should inform their doctor that they are taking biotin pills or multivitamins with biotin to ensure accurate test results. If the patient is taking biotin, stop taking biotin at least 12 hours before the blood draw.
When the patient is diagnosed with hyperthyroidism, the doctor will assign the patient to perform some more tests to determine the cause of the disease such as: radioiodine absorption test, thyroid scan, thyroid ultrasound.

There are different ways to treat an overactive thyroid aka hyperthyroidism. Before choosing a medication that is right for you, you should consult with your doctor, who will consider the cause of the disease, age, overall health and severity of the disease. symptoms to prescribe the right medication.
Methimazole and propylthiouracil are medications for hyperthyroidism that help control symptoms and may provide long-term benefits. However, these drugs will usually relieve your symptoms within 3 months, although you will likely have to take them for up to 18 months to help reduce your risk of recurrence. Importantly, methimazole has less serious side effects, so it is prescribed more often.
Below are some of the common medications used to treat hyperthyroidism.
2.1 Radioactive iodine pills
This is a medicine that is taken orally to help shrink a patient's thyroid gland. The drug is effective after 3 to 6 months of use. Doctors have been prescribing radioactive iodine to treat hyperthyroidism for over 60 years, which is considered safe and is used to treat more than 70% of adults with hyperthyroidism. . The dose of radiation used during radioactive iodine treatment is very low, but there are some precautions to take after treatment:
Avoid prolonged close contact with children and women pregnant for a few days or weeks Women should avoid becoming pregnant for at least 6 months Men should not father a child for at least 4 months Radioactive iodine treatment is not suitable for women who are pregnant or for children suck. It is also not appropriate if your overactive thyroid is causing serious eye problems.
However, because the main effect of the drug is to shrink the thyroid gland, making the patient's thyroid gland slow down, putting the patient at risk of hypothyroidism. When this happens, the patient's thyroid becomes underactive, and the patient needs daily thyroid hormone replacement medication.

2.2 Antithyroid drugs
In some cases, when an overactive thyroid is treated with drugs that block the ability of thyroid hormone production such as methimazole and propylthiouracil where methimazole has few serious side effects. should be used in prescriptions more often by doctors. These drugs help control, relieve symptoms of the disease within 3 months and provide long-term benefits. However, patients should take the drug for up to 18 months to reduce the risk of the disease coming back.
However, according to some studies, it has been shown that about 3% of patients taking anti-thyroid drugs develop allergic reactions such as rash and urticaria. In some more severe cases, these drugs can cause a condition called agranulocytosis, which reduces a patient's white blood cell count. When this is the case, the patient has an increased incidence of some type of infection compared to the general population. Besides, the patient's liver is also at risk of damage. If patients develop symptoms such as fever and sore throat while taking these medications, they should see a doctor immediately.
2.3 Beta blockers
These drugs do not work to change the amount of thyroid hormone in the patient's body but it can help the patient control the symptoms of hyperthyroidism by stopping excess hormone production excess in the thyroid gland. Typically, beta-blockers are used to treat high blood pressure or to help slow the heart rate. Once the patient's thyroid hormone levels are under control, the patient can reduce the dose then stop. But some people still need to continue taking the medication for several years or for the rest of their lives.
However, when using this medicine for the first few months, patients may experience some side effects such as feeling tired, headache, dizziness, high body temperature, joint pain, experiencing symptoms. digestive problems (swelling, change in taste), itchy rash,... but at a mild level the patient can still use the drug
A less common but serious side effect Rather, a sudden drop in a patient's granulocyte count can lead to infection. When a patient has symptoms of agranulocytosis such as high temperature, sore throat, persistent cough, a blood test should be arranged to check the patient's white blood cell count.

2.4 Surgery
Surgery is generally not recommended in patients with hyperthyroidism, but in patients receiving antithyroid drugs or radioactive iodine therapy who have failed to respond to the condition Your doctor may recommend a thyroidectomy. The patient has symptoms such as:
Your thyroid gland is severely swollen Have serious eye problems caused by an overactive thyroid No other, less invasive treatments are available. you come back after trying other treatments Surgery means the patient's thyroid gland is completely removed from the body. However, surgery always comes with risks such as damaging the patient's vocal cords and parathyroid glands (it's located behind the thyroid). These glands help control the amount of calcium in the patient's blood. After surgery, when the patient participates in activities, it is necessary to use medicine to provide the body with the amount of hormone that the thyroid gland secretes. If the patient's parathyroid glands are also removed, another medication will be needed to keep the patient's blood calcium level stable.
Like all medications, hyperthyroidism has its own advantages and limitations. Each drug works very well for the patient, but there are still unwanted side effects. However, if these side effects do not affect the patient's daily activities and health, they can continue to use it. To avoid recurrence of hyperthyroidism, the patient should be persistent in taking the drug regularly and for about 18 months, depending on the patient's condition.

Currently, Vinmec International General Hospital is one of the most popular places to visit and screen for thyroid diseases. When choosing Vinmec, you will be examined by experienced thyroid specialists, helping to screen and early detect common thyroid diseases such as simple goiter, hyperthyroidism, hypothyroidism, thyroiditis, thyroid nodules, thyroid cancer,...
At the same time, you will have blood tests, evaluate the levels of thyroid function hormones such as FT3, FT4, TSH, Anti – TPO, Anti-TG and ultrasound, scan to evaluate the structure of the thyroid gland. After that, when the results are returned to the doctor, you will be consulted about thyroid pathology, and discuss the appropriate treatment options for yourself. From there, thyroid disease will be prevented in time, avoiding long-term health damage in the future.

References: webmd.com, mayoclinic.org, nhs.uk, ncbi.nlm.nih.gov