Endocrine Drug Introduction Endocrine medications can be broken down into the following categories diabetic agents hormone agonists hormone antagonists Endocrine Drug Table Diabetic Agents Name Mechanism of Action Key Indication(s) Key Toxicity Sulfonylureas (1st Generation) Chlorpropamide Inhibits ATP-sensitive K+ channels resulting in β-cell depolarization and insulin release Second-line treatment for type II diabetes Hypoglycemia (long-lasting) Renal failure Disulfiram effects Tolazamide Tolbutamide Sulfonylureas (2nd Generation) Glipizide Inhibits ATP-sensitive K+ channels resulting in β-cell depolarization and insulin release Second-line treatment for type II diabetes Hypoglycemia (long-lasting) Renal failure Glyburide Biguinides Metformin Exact mechanism unknown ↓ gluconeogenesis ↑ insulin sensitivity ↑ glycolysis ↓ serum glucose levels ↓ postprandial glucose levels First-line treatment for type II diabetes and metabolic syndrome Lactic acidosis in patients with poor renal function Alpha-Glucosidase Inhibitor Acarbose Prevents breakdown of carbohydrates into single glucose molecules decreasing rate of absorption Refractory type II diabetes mellitus Osmotic diarrhea Flatulence Miglitol Thiaglitazone Pioglitazone Stimulates PPAR-γ which controls insulin-sensitive genes resulting in increased insulin sensitivity in peripheral tissues Type II diabetes combination therapy Heart failure Hepatotoxicity Weight gain Troglitazone Rosiglitazone Other Repaglinide Inhibits ATP-sensitive K+ channels resulting in β-cell depolarization and insulin release Type II diabetes combination therapy Hypoglycemia Hormone Agonists Estrogen Polyestradiol Inhibits actions of dihydrotestosterone Blocks LH secretion by pituitary Decreases testosterone synthesis Blocks testosterone uptake into prostate cells Inhibits 5α-reductase Induces chemical castration Palliative prostate cancer therapy Feminization Nausea Headache Water retention Diethylstilbestrol Inhibits HPG axis Blocks testosterone synthesis Induces chemical castration Believed to decrease incidence of stillbirth No longer used in the US Clear cell carcinoma (of the fetus) Vaginal adenosis T-shaped uterus Progestins Megestrol acetate Synthetic progestin suppresses leuteinizing hormone by inhibition of pituitary function Anorexic mechanism unknown Appetite stimulant Anti-neoplastic agent Weight gain Nausea Vomiting Gonadotropin Releasing Hormones Leuprorelin Acts as a gonadotropin releasing hormone agonist which inhibits gonadotropin secretion Hormone responsive cancer (non-pulsatile) Fertility (pulsatile) Flushing Sweating Fatigue Edema Skin reaction Hormone Antagonists Anti-Estrogens Tamoxifen Competitively binds to estrogen receptors inhibiting effects of estrogen ER/PR positive breast cancer Endometrial cancer Growth plate fusion Increased bone density Anti-Androgens Flutamide Blocks action of testosterone by binding to adrogen receptors Prostate cancer (used prior to GnRH analogues) Gynecomastia GI disturbance Enzyme Inhibitors Anastrozole Inhibits aromatase ER/PR positive breast cancer Fertility Osteoporosis Bone fracture