Pharmacology: Chapter 36: Drugs Used to Treat Thyroid Disease

Anti-Thyroid Medicines: Actions

Block synthesis of T3 and T4

Iodine-131: Administration

Iodine added to water and swallowed Minimize exposure; wear latex gloves to administer or to dispose of patient's excreta If medication or excreta spills, follow agency policy and use containers for radioactive waste disposal

Anti-Thyroid Medicines: Drugs

Iodine-131 A radioactive isotope of iodine Propylthiouracil (PTU, Propacil), Methimazole (Tapazole)

Thyroid Replacement Hormones: Drugs

Levothyroxine, liothyronine, liotrix

Iodine-131: Drug Interactions

Lithium Carbonate

Anti-Thyroid Medicines: Uses

Long-term treatment for hyperthyroidism Pre-surgical treatment to block new production before surgery. By the time the gland is removed, medications can be started without having all those thyroid hormones circulating.

Thyroid Replacement Hormones: Special Considerations

Needs to stay on the same brand; subtle changes in the composition can have a big effect Needs to have blood work done regularly; dose will need to be adjusted periodically If they've had a thyroidectomy, the medication needs to be taken for life

Anti-Thyroid Medicines: Common and Serious Adverse Effects

Purpuric, maculopapular rash; headache; nephrotoxicity; hepatotoxicity; bone marrow suppression; lymph node enlargement

Thyroid Replacement Hormones: Actions

Replace deficient T3 and T4 hormones

Thyroid Replacement Hormones: Uses

Return patient to normal thyroid state

Iodine-131: Actions

Selectively destroys hyperactive thyroid tissue

Thyroid Replacement Hormones: Common and Serious Adverse Effects

Signs of hyperthyroidism; hyperglycemia

Iodine-131: Common and Adverse Effects

Tenderness in the thyroid gland; hyperthyroidism; hypothyroidism

Iodine-131: Uses

Treat hyperthyroidism for select individuals Benefits noticed in 3 to 6 months

Anti-Thyroid Medicines: Drug Interactions

Warfarin dosage may have to be increased Digoxin dosage may have to be decreased

Thyroid Replacement Hormones: Drug Interactions

Warfarin, digoxin, estrogens, cholestyramine Need increased dosage of anticoagulants, decreased dose of digoxin