Antihypertensive drugs Flashcards
1
Q
Diuretics
A
- Thiazides (Hydrocholthiazide)
- Loop diuretics (Furosemide
- Can be used as first-line therapy for hypertension
- Super to β-blockers for treating hypertension in older adults
2
Q
Thiazides and their mechanism
A
- Hydrochlorthiazide, Chlorthalidone
- Inhibit sodium chloride transport in early segment of distal convoluted tubule
- Produce:
- Na and Cl diuresis
- Hypercalcemia (enhance Na/Ca-exchanger)
- Hyponatremia
- Hypokalemic alkalosis (since increased Na is presented to the collecting tubule)
- Hyperuricemia
- Hyperglycemia
- Used to treat mild hypertension
3
Q
Loop diuretics and their mechanism
A
- Furosemide, Bumetanide, Torsemide
- Inhibit cotransport of sodium, potassium and chloride in the thick ascending limb
- Produce:
- Na and Cl diuresis
- Hypocalcemia
- Hypokalemic alkalosis (since increased Na is presented to the collecting tubule)
- Used to treat moderate, severe and malignant hypertension
4
Q
Potassium-sparing diuretics
A
- Amiloride, Triamterene –> Inhibit sodium transport in late distal and collecting duct
- Spironolactione, Eplerenone –> Aldosterone receptor blockers
5
Q
Sympathplegics
A
- α2-selective agonist: Clonidine, Methyldopa
- Postganglionic sympathetic nerve terminal blockers: Reserpine, Guanethidine
- α1-blockers: Prazosin
- β-blockers: Propranolol, Metoprolol, Atenolol
6
Q
Clonidine
A
- α2-selective agonist
- Stimulation of α2 receptors in CNS cause decrease in sympathetic outflow
- Decreased NE release:
- No α1 stimulation –> decreased TPR
- No β1 stimulation –> decreased HR
- Used to treat mild-to-moderate hypertension
- Comensatory response is salt and water retention
- Adverse effects: dry mouth, rebound hypertension if suddenly stopped, sedation
7
Q
Methyldopa
A
- α2-selective agonist
- Stimulation of α2 receptors in CNS cause decrease in sympathetic outflow
- Decreased NE release:
- No α1 stimulation –> decreased TPR
- No β1 stimulation –> decreased HR
- Used to treat mild-to-moderate hypertension
- Comensatory response is salt and water retention
- Adverse effect: sedation, positive Coombs test, hemolytic anemia
8
Q
Reserpine
A
- Postganglionic sympathetic nerve terminal blocker
- Deplete the adrenergic nerve terminal of its NE stores
- Very efficacious, but high incidence of adverse effects
- Readily enters the CNS
- Adverse effects: behavioral depression, diarrhea, nasal stuffiness, sedation
9
Q
Prazosin
A
- α1-blocker
- Decrease peripheral vascular resistance and lower arterial blood pressure
- Used to treat mild-to-moderate hypertension combined with propranolol and/or a diuretic
- Adverse effect: orthostatic hypotension
10
Q
β-blockers
A
- Propranolo, Metoprolol, Atenolol
- Reduce blood pressure by primarily decrease CO
- May also inhibit renin release
- First-line drug therapy for hypertension in post-MI patients or in patients with a previous MI
- Useful in treating HT in patient with angina pectoris, CHF, SVT
- More effective to treat HT in white and young patients
- Adverse effects: sleep disturbances, sedation, impotence, cardiac disturbances, asthma
11
Q
ACE inhibitors
A
- Captopril, Enalapril, Lisinopril
- Recommended in treating HT when the first-line agents are contraindicated
- Used to treat HT in patients with diabetes
- Decrease angiotensin II and increase bradykinin levels
- Decrease aldosterone levels
- Reduce cardiac preload and afterload, thereby decreasing cardiac work
- First-line drugs for treating HF, HT in patins with chronic renal disease, and for patients with increased risk for coronary artery disease
12
Q
ARBs
A
- Losartan, Valsartan
- Block AT1 receptors, decreasing the activation of the receptors by ATII
- Produce arteriolar and venous dilation and block aldosterone secretion
- Reduce cardiac preload and afterload, thereby decreasing cardiac work
13
Q
Ca-channel blockers
A
- Verapamil, Diltiazem, Nifedipine
- Effective in treating hypertension in patients with angina or diabetes
- Nifedipine have much greater affinity for vascular Ca-channels than in heart. It is therefor particularly attractive in treating HT
14
Q
Nitroprusside
A
- Release of NO, which increase cGMP in vascular smooth muscle - vasodilation
- Used in hypertensive emergencies
- IV infusion
- Adverse effect: cyanide toxicity (treated with sodium thiosulfate)
15
Q
Hydralazine
A
- Release NO from endothelial cells
- More effect on arterioles than on veins
- Adverse effect: lupus-like syndrome, reflex tachycardia, nausea, edema
- Used to treat moderately severe HT
