Drugs Of Hyperthyroidism Flashcards
What are the mechanisms of drugs that treat hyperthyroidism?
1- inhibiting synthesis of thyroid hormones.
2- Destruction of the gland by radiation.
3- Blocking hormone release.
4- Miscellaneous mechanisms.
What is the mechanism of thiocyanate?
In large doses can inhibit organification of iodine.
What are inhibitors of iodine uptake?
Thiocyanate, Perchlorate, & fluoroborate.
What is the action of perchlorate?
Ten- fold more effective than thiocyanate.
What is the adverse effect of iodine inhibitors?
Severe aplastic anemia.
What is the action of the iodide?
1- reduces vascularity of the thyroid gland.
2- gland becomes firmer.
3- colloid re-accumulates in the follicles.
4- Quantity of bound io
When is maximal effect of iodide achieved?
10-15 days
What are adverse effects of iodide?
Angioedema, rash, metallic taste, hypersensitivity reactions, ulcerations of mucous membranes.
What is contraindication of iodide?
Pregnancy: fetal goiter.
What are thioamines?
1- Propylthiouracil: inhibit the conversion of T4 to T3.
2- Methimazole: more potent & longer half-life.
What is the mechanism of action of thioamines?
Inhibits peroxidase enzyme.
What is mechanism of action of thioamines?
Effective orally, half life 1-2 hrs, excreted in urine as glucuronides (found in enterohepatic circulation).
What are the adverse effects of thioamines?
Rashes, headache, nausea, leucopenia, agranulocytosis, goiter.
What are indications of radioactive iodine (I131)?
Concentrated in thyroid gland, treat thyrotoxicosis,evaluate thyroid responsiveness, alternative to surgery.
What is indication of atenolol (B- adrenergic antagonists)?
Prevent complication arising from thyroxine- induced enhanced sympathetic activity.
