Methimazole is an antihyperthyroid drug used to treat hyperthyroidism, particularly in Graves' disease. The drug reduces the synthesis of thyroid hormones by blocking tyrosine peroxidation in thyroid follicles. An important aspect is the antenatal effect of methimazole on the embryo, which is associated with potential risks for fetal development. Methimazole, penetrating the placental barrier, can lead to various side effects, including the development of low birth weight in newborns, as well as early or late thyroid dysplasia and heart defects. Studies demonstrate the need for careful monitoring of pregnant women taking this drug in order to minimize adverse outcomes.
History of the disease and interesting historical facts
The history of methimazole dates back to the 1920s, when the drug was first synthesized and used to reduce thyroid function. In the 1940s, methimazole became popular among specialists due to its high efficacy rates and relative safety compared to previous antihyperthyroid drugs. Interestingly, methimazole was also used to treat other conditions at the beginning of its use, but soon focused on hyperthyroidism. An important step in the development of methimazole therapy was a study conducted in the 1950s that indicated its ability to improve the condition of patients with thyrotoxicosis, which became the basis for its wider use.
Epidemiology
According to various studies, the prevalence of hyperthyroidism in the population ranged from 0.5% to 1.5% for adults, but among women this figure is significantly higher and can reach 2% or more. It is worth noting that the disease is most often diagnosed in women aged 20 to 40 years. Given the antenatal effects of methimazole, statistics show that the use of the drug during pregnancy affects a considerable number of cases: one of the large cohort studies found that approximately 15% women with hyperthyroidism at the time of conception continue drug therapy with methimazole. The risks associated with the use of this drug during pregnancy predetermine the importance of conducting research to determine the possible consequences for the offspring.
Genetic predisposition to this disease
Genetic predisposition to hyperthyroidism is more likely to depend on a combination of various genetic and environmental factors. One of the key factors is HLA (antigen of a protein necessary for the formation of an autoimmune reaction). Studies show that certain alleles, such as HLA-B8 and HLA-DR3, may be associated with an increased predisposition to Graves' disease. Also, scientific papers have raised the question of the presence of a mechanism for binding to genes such as CTLA-4 and PTPN22, which are involved in the regulation of the immune response. Thus, the pathogenesis of the disease may have multigenic mechanisms that contribute to its occurrence both in the case of its presence in close relatives and with changes in the genetic material.
Risk factors for the development of this disease
There are many factors that contribute to the development of hyperthyroidism, among which the following can be distinguished:
- Genetic factors – presence of cases of hyperthyroidism in the family.
- Stressful situations that lead to significant changes in the body.
- Nutritional deficiencies - lack of iodine, which is a key element in the synthesis of thyroid hormones.
- Professional activities involving chemicals - working with phosphorus, benzene and some other toxins.
- Chronic infections, such as viral diseases, that can affect the immune response.
- Diabetes mellitus and other autoimmune diseases increase the risk of developing hyperthyroidism.
Diagnosis of this disease
The main symptoms of hyperthyroidism are:
- Enlarged thyroid gland (goiter).
- Increased heart rate, arrhythmia, high blood pressure.
- Weight loss despite normal or increased appetite.
- Anxiety, restlessness, irritability.
- Increased sweating and fever.
Laboratory tests include:
- Determination of the level of thyroid hormones (T3, T4).
- Measurement of thyroid stimulating hormone (TSH).
- Test for antibodies to TSH receptors.
Radiological examinations may use:
- Ultrasound examination of the thyroid gland.
- Scintigraphy to determine the functional activity of nodular formations.
Other diagnostic methods include:
- General and biochemical blood tests.
- ECG to detect arrhythmias.
Differential diagnosis includes exclusion of diseases such as thyroiditis, benign or malignant thyroid tumors, and other types of thyroid dysfunction.
Treatment
Treatment of hyperthyroidism includes several directions:
- General treatment consists of normalizing thyroid hormone levels and eliminating the symptoms of hyperthyroidism.
- Pharmacological treatment: Methimazole is the mainstay of treatment, but propylthiouracil and beta blockers may also be used to control symptoms.
- Surgical treatment may be indicated for large goiters or when drug therapy is ineffective.
- Other treatments include radioiodine therapy, which involves ablation of the thyroid gland with radioactive iodine.
List of medications used to treat this disease
The main drugs used to treat hyperthyroidism include:
- methimazole
- Propylthiouracil
- Beta blockers (eg, atenolol, propranolol)
- Iodine solutions
- Radioactive iodine
Disease monitoring
Monitoring of patients with hyperthyroidism includes regular:
- Control tests of T3, T4 and TSH levels every 2-3 months.
- Assessment of the thyroid gland using ultrasound.
- Conducting an ECG to assess cardiovascular health.
The prognosis with timely treatment is usually favorable, but complications such as thyrotoxic crisis or the development of osteoporosis due to long-term use of glucocorticoids or uncontrolled use of methimazole are possible.
Age-related features of the disease
Hyperthyroidism can manifest itself differently in different age groups:
- In children, signs of the disease may be more pronounced and develop quickly, including sudden weight loss and behavior changes.
- In adult women of reproductive age, hyperthyroidism is often associated with pregnancy and its consequences for fetal development.
- In older people, symptoms may be less typical and less pronounced, making diagnosis more difficult and treatment less effective.
Questions and Answers
- How does methimazole affect pregnancy? Methimazole can cross the placental barrier and cause various complications, including fetal developmental disorders.
- What are the symptoms of hyperthyroidism you should know? The main symptoms include an enlarged thyroid gland, weight loss, rapid heartbeat and increased sweating.
- How often should hormone levels be monitored while taking methimazole? It is recommended to monitor the levels of T3, T4 and TSH every 2-3 months during therapy.
- What to do if side effects from methimazole occur? If side effects occur, you should immediately consult a doctor to adjust your treatment.
- What are the main treatments for hyperthyroidism? The main treatment methods include drug therapy, radioiodine therapy and surgery if necessary.
One thought on “Антенатальное воздействие метимазола”
My cousin and I were both born in the early 1960's with a circular 50p size bald patch on our head where hair has never grown. One of our mother's suffered hypothyroidism and the other hyperthyroidism. Both were on tablets to aid conception of their first child at the time - highly likely to have been methimazole. I believe this defect was a side effect of this drug. I have been told as a consequence I may also be susceptible to the development of early cataracts.