Drugs Affecting the Endocrine System

Drugs Affecting the Endocrine System Pharmacology overview: ● Thyroid replacement drugs: Natural thyroid preparation: Thyroid. Synthetic thyroid preparations: levothyroxine, liothyronine and liotrix. Mechanism of action: The thyroid drugs work in the same manner as the endogenous thyroid hormones, affecting many body systems. Indications: Levothyroxine is the preferred drug because its hormonal content is standardized; therefore, its effect is predictable Contraindications: Contraindications to thyroid preparations include known drug allergy to a given drug product, recent myocardial infarction, and hyperthyroidism. Adverse effects: Cardiac dysrhythmia is the most significant adverse effect Toxicity: Related to T4 levels. Nervousness. Heart palpitations. Intolerance to heat. Weight loss. Interactions: May enhance the activity of oral anticoagulants. May decrease serum digitalis levels. Diabetic patients may require increased dosages of their hypoglycemic drugs. Levothyroxine: Its half-life is long enough that it only needs to be administered once a day. It is available in oral form and in parenteral form. Pregnancy category A. Given once daily at morning before food ½ to 1 hour. Steady state is achieved in 6-8 weeks. ● Antithyroid Drugs: The treatment of hyperthyroidism may aim at treating either the primary cause or the symptoms of the disease. Antithyroid drugs, iodides, ionic inhibitors, surgery, and radioactive isotopes of iodine are used to treat the underlying cause, and drugs such as beta-blockers are used to treat symptoms. Here we will focus on the antithyroid drugs.