EXAM #2: CV PHARM V Flashcards
What is the mechanism of action of the Thiazide diuretics?
Block the NaCl Cotransporter (NCC) in the distal collecting tubule
Recall that NKCC inhibitors are LOOP diuretics, NOT thiazide diuretics
What are the major side effects of NCCs?
- Ca++ reabsorption
- Vasorelaxation
Why is there reduced Ca++ excretion with the NCC’s?
- Ca++ in the DCT is under the control of parathyroid hormone (PTH)
- Thiazide stimulates PTH to cause increased Ca++ reabsorption
Why is there loss of K+ with NCC’s?
Increased solute concentration in the lumen stimulates K+ excretion
What are the clinical indications for NCC Inhibitors?
1) HTN (note that K+ loss in these patients can be bad)
2) CHF
3) Hypercalciuria
4) Nephrolithiasis (calcium renal stones)
5) Nephrogenic Diabetes Insipidus
**Note that hypercalciuria increases the likelihood of kidney stones
What is Nephrogenic Diabetes Insipidus?
Decreased expression of aquaporins that would normally cause water-reuptake leads to water LOSS
Why are Thazide DIURETICS used in Nephrogenic Diabetes Insipidus?
1) Increased renal Na+ reabsorption in patients with DM-Insipidus
2) Recovery of aquaporin 2 abundance
3) Recovery of NCC, ENaC
List the thiazide diuretics.
Chlorathalidone
Hydrochlorothiazide
Metolazone
Indapamide
What is the mechanism of action of the inhibitors of renal epithelial Na+ channels?
- Normally in the DCT, Na+ is absorbed via epithelial channels in the apical membrane of the lumen; K+ is secreted
Block epithelial Na+ channels on principle cells in the late DCT and K+ is not longer secreted
Why are the epithelial Na+ channel blockers K+ sparing?
Block epithelial Na+ channels on principle cells in the late DCT and K+ is not longer secreted
What are the clinical indications for epithelial Na+ channel blockers?
1) Hypokalemic alkalosis
2) Used in combination with other diuretics to PREVENT HYPOKALEMIA
List the K+ sparing diuretics.
Amiloride
Triamterene
What is the mechanism of action of the aldosterone-receptor antagonsists?
1) Recall that aldosterone stimulates Na+ reabsorption in renal collecting tubules; water following
2) ANTAGONIZE aldosterone receptors in collecting tubules and DECREASE Na+ reabsorption
Note that K+ loss if also limited in these diuretics.
What are the pleotropic effects of the aldosterone receptor antagonists?
1) Prevention of LV remodeling and cardiac fibrosis
2) Prevention of sudden cardiac death
3) Anti-hypertensive
4) Reduces the generation of ROS
Thus, these drugs are commonly given to patients with CHF, post-MI.
Why is cardiac remodeling negative?
This is the process that leads to hypertrophy and hyperplasia of the cardiac tissue that happens in patients s/p MI that eventually leads to DEATH
What are the clinical indications for Aldosterone receptor antagonisnts?
1) Edema and HTN
2) CHF
3) Primary hyperaldosteronism
4) Refractory edema with secondary aldosteronism
What causes secondary aldosteronism?
- HF
- Hepatic cirrhosis
- Nephrotic syndrome
- Severe ascites
These are associated with an increase in aldosterone b/c the body thinks that it doesn’t have enough water and increases the secretion of aldosterone
What are the adverse effects of the aldosterone receptor antagonists?
1) Hyperkalemia
2) Metabolic acidosis in cirrhotic patients
3) Hormonal effects including
- Gynecomastia
- Impotence
- Decreased libido
- Hirsutism
- Deepening of the voice
- Menstrual irregularity
List the aldosterone receptor antagonists.
Spironolactone
Eplerenone
What is the definition of chronic systemic arterial hypertension?
140/90 mmHg
What is a hypertensive crisis?
BOTH urgency and emergency
What is hypertensive urgency?
Systolic BP > 180
Diastolic BP > 120
WITH NO associated acute end organ damage; decrease BP within a few minutes to hours
What is a hypertensive emergency?
Markedly elevated BP with acute end organ damage
Decrease blood pressure within minutes to an hour*
What are the organs that are specific to end organ damage?
Heart
Kidney
Brain
Retina
