Pharmacology Mnemonics - Flash Cards

Name: Radioactive Iodine

Class: Antithyroid Drug

Mechanism: Trapped by thyroid. b particles cause highly localized tissue destruction. X-rays are diagnostically useful. I¹³¹ generally used due to short t½ (8 d).

Absorption: 90% ends up in thyroid or urine. 10% absorbed by the rest of the organ systems.

Dist.: Metabolism.:

Excretion, t½: Urine. 8 d.

Toxicity/S.E.s: High incidence of hypothyroidism (5-10% in 1-2 yr., eventually 50%). May require multiple exposures—up to a year (thioamides usu. used to cover hyperthyroidism in the interim). C/i in pregnant E and kids.

Utility: Treat hyperthyroidism w/o surgery. Indicated for old folk (esp. w/heart disease), when subtotal thyroidectomy or thioamides have not worked, and especially for some metastatic thyroid cancers where cells continue to take up iodide and respond to TSH. Used to evaluate thyroid fxn (e.g., hypo/hyperthyroidism, goiter types, response to TSH/TRF.).

Special Features: Min. dose = 80-150 mCi/g thyroid or 4-10 mCi total. Estimate w/tracer dose to determine uptake.

Name: Iodide

Class: Antithyroid drug

Mechanism: High doses of iodide inhibit thyroid gland fxn. Effects decrease w/time, possible due to decrease in iodide transport.

Absorption:

Dist.:

Metabolism.:

Excretion, t½:

Toxicity/S.E.s:

Utility: Used in conjunction w/thioamides for preoperative preparation to diminish vascularity and swelling of thyroid gland ® reduced operative mortality. Treatment of thyrotoxicosis. Blocks synthesis and release of thyroid hormones. Rapid effect.

Special Features: No longer used very much.