Pharmacology of Adrenal Steroids Flashcards
What is dexamethasone
A synthetic analog of cortisol. This ends up inhibiting ACTH and endogenous corticosteroid production because the body thinks it has tons already
Name 3 Inhaled corticosteroids
- Fluticasone
- Mometasone
- Beclomethasone
Beclomethasone has few systemic side effects because….
It is rapidly metabolized in the lung
Fluticasone and Mometasone have few systemic side effects because….
They both undergo lots of first-pass hepatic metabolism
Name 3 corticosteroid antagonists
- Mifepristone (cortisol antagonist)
- Spironolactone (aldosterone antagonist)
- Eplerenone (selective mineralocorticoid antagonist)
What are some specific uses for Mifepristone (cortisol antagonist)
- Hyperglycemia in Cushing’s syndrome pt’s who are not surgical candidates
- Early term abortions (blocking progesterone)
What are some specific uses for Spironolactone (aldosterone antagonist)
- Hypertension
2. CHF after AMI
What are some specific uses for eplerenone
- Hypertension
2. CHF
Name 2 inhibitors of adrenal steroid synthesis
- Metyrapone
2. Aminoglutethimide
What does metyrapone do?
Inhibits 11β-hydroxylation reaction in biosynthesis (can’t convert 11-deoxycorticostrone (DOC) to corticosterone, which means you can’t make aldosterone)
What does aminoglutethimide do?
Inhibits the conversion of cholesterol to pregnenolone (first committed step in adrenal steroid biosynthesis)
What is the role of 11β-hydroxysteroid dehydrogenase
Normally, this enzyme converts cortisol to cortisone (not as potent) in the kidney. This happens because the mineralocorticoid receptors bind cortisol with more affinity than aldosterone (mostly because there’s a shit ton more cortisol floating around than aldosterone), and we need the kidneys to be able to respond to aldosterone so our BP stays in check.
Fun fact: licorice inhibits this enzyme!
