SM 133a - Hypertension Pathophysiology and Pharmacology Flashcards
(48 cards)
What is the threshold for medical hypertension treatment if a patient has >10% risk of developing heart disease?
Blood pressure should be treated if it is >130 systolic or >80 diastolic
What is the threshold for medical hypertension treatment if a patient has <10% risk of developing heart disease?
Blood pressure should be treated if it is >140 systolic or >90 diastolic
Home blood pressure readings over the course of 1 week measure 125/85
Which blood pressure category does this fall into?
Stage I Hypertension
(130-139 systolic or 80-89 diastolic)
List the ranges for each category. Note: if systolic and diastolic fall into different categories, go with the higher classification
Normal:
Elevated:
Stage I Hypertension:
Stage II Hypertension:
Normal: <120/<80
Elevated: 120-129/<80
Stage I Hypertension: 130-139/80-89
Stage II Hypertension: >140/>90
How many measurements are required to make a diagnosis of hypertension?
At least 2
What are the 3 major physiologic determinants of blood pressure?
Volume: Stroke volume and total blood volume
Vascular tone
Cardiac Output
List the mechanisms by which Angiotensin II effects blood pressure
- Sympathetic activation
- Smooth muscle vasoconstriction
- Decreased bradykinin -> Prevention of vasodilation
- Na+ and H2O retention
- By increasing aldosterone in the adrenal cortex
- By increasing ADH in the brain
What are the 4 options for first-line hypertension treatment?
- Thiazide diuretics
- Hydrochlorothiazide
- ACE inhibitors
- -pril drugs
- ARBs
- -sartan drugs
- Calcium Channel Blockers
- Verapamil, Diltiazem, Nifedipine
Describe the mechanism and site of action of thiazide drugs
Thiazides like hydrochlorothiazide and chlorthalidone block the Na+-Cl- symporter in the distal convoluted tubule
This traps Na+ in the urinary space, leading to increased K+ excretion via Na+/K+ exchanger activity
(Can combine with an ACE inhibitor to preserve K+)
Give 2 examples of thiazide drugs
hydrochlorothiazide and chlorthalidone
Describe the mechanism and site of action of furosemide, torsemide, and bumetanide
The -(m/n)ide drugs are loop diuretics
They block the Na+-K+-2Cl- symporter in the thick ascending limb of the loop of Henle
This traps these ions in the urinary space, leading to acute volume loss. They are best used for rapid diuresis, while thiazides are better tolerated in the long term
Which diuretics are effective for acute volume loss, but are not recommended for long-term therapy (except in patients who have chronic kidney disease)?
Loop duretics: Furosemide, torsemide, and bumetanide
Note: combine with saline if the patient is hypercalcemic
What blood pressure measurements constitute a hypertensive emergency?
SBP>180 or DBP >120
List 4 K+ sparing diuretics
- Renal epithelial Na+ channel blockers
- Triamterene
- Amiloride
- Renal epithelial mineralcorticoid receptor blockers
- Spironolactone
- Eplerenone
List 3 loop diruetics
Who are these drugs recommended for?
Furosemide, torsemide, and bumetanide
Effective for acute volume loss, but are not recommended for long-term therapy (except in patients who have chronic kidney disease)
Note: combine with saline if the patient is hypercalcemic
Which drugs act by blocking the renal epithelial Na+ channels in the late distal tubule and collecting duct?
Triamterene
Amiloride
(K+ sparing diuretics)
Describe the mechanism and site of action of Triamterene and Amiloride
Triamterene and Amiloride act by blocking the renal epithelial Na+ channels in the late distal tubule and collecting duct of the kidney. They are K+ sparing diuretics
If less Na+ gets into the epithelial cells, less K+ is expelled from them (via decreased activity of the Na+/K+ exchanger)
Describe the mechanism and site of action of spironolactone and eplerenone
Spironolactone and eplerenone are aldosterone receptor antagonists. They block mineralcorticoid receptors (aka the aldosterone receptor) on epithelial cells in the late distal tubule and collecting duct of the kidney. They are K+ sparing diuretics
If less Na+ gets into the epithelial cells, less K+ is expelled from them (via decreased activity of the Na+/K+ exchanger)
What drugs would you give to a hypertensive patient despite thiazide therapy who is also hypokalemic?
K+ sparing duretic
Tiamterene, amiloride, spironolactone, or eplerenone
Describe the effects of aldosterone on blood pressure
Aldosterone acts on the distal nephron to increase blood pressure by promoting Na+ absorption
By promoting the absorption of Na+, K+ and H+ are excreted
Describe the mechanism of action of clonidine
Clonidine is an adrenergic alpha2 receptor agonist
The alpha2 receptors is located on the presynaptic sympathetic neuron. It usually functions as a feedback mechanism that senses and then downregulates norepinephrine.
Clonidine “artificially” stimualtes the alpha2 receptors, thus inhibiting norepinephrine release and preventing vasoconstriction
Which blood pressure medication is an alpha2 adrenergeic receptor agonist?
Clonidine
Describe the mechanism of action of methyldopa
Methyldopa replaces norepinephrine in secretory vescicles of adrenergic neurons.
This blocks central adrenergic outflow through negative feedback mechanisms, thus inhibiting vasoconstriction
Which blood pressure medication replaces norepinephrine in secretory vescicles of adrenergic neurons?
Methyldopa
