Week 3: pharmacology of antihypertensive drugs Flashcards
1
Q
How are adrenergic blocking drugs used in the treatment of HTN?
A
Drugs used: metoprolol (lipid soluble), atenolol (water soluble), Carvedilol (beta and alpha1 blocker)
- decrease chronotropic and inotropic activity of the heart
- decrease adrenergically stimulated secretion of renin in the kidney
- slow onset of action in reducing arterial pressure
2
Q
What are the side effects of beta blockers?
A
- b2 antagonist activity-vasoconstrictiona and bronco constriction, caution with patients with peripheral vascular disease and asthma
- lipid soluble beta blockers (metoprolol) cross BBB-nightmares and depression
- decrease HDL and increase LDL and TGs, caution with patients with hyperlipidemia
- blocks reflex to increase glucose when it is low. In diabetics taking insulin, if glucose levels too low, Epi and NE secreted to stimulate release of glucose. Also stimulates cardiac reflex that increases HR, which warns diabetics they have low glucose. But beta blockers interfere with warning sign.
- African americans and elderly don’t respond well. Young and caucasians do.
3
Q
What are the classes of diuretics? Which are preferred?
A
- Thiazide diuretics: hydrochlorothiazide. act on early segment of distal convoluted tubule. Most effective for essential HTN. Preferred.
- Loop diuretics: Furosemide. Act on loop of henle. equally effect as thiazide but more side effects.
- potassium sparing diruretics: triamterene, amiloride. Act on distal tubule. can be used in combo with thiazide to prevent hypokalemia.
4
Q
Describe the early and late effect of treatment with hydrochlorothiazide.
A
- early: Na and water excreted and fluid volume drops. Drop in bp invokes cardiac reflex to increase peripheral resistance. but fluid volume stays lowered and so does bp.
- late: arteriole dilation takes place and bp stays down. mechanism unknown.
- hydrochlorothiazide is effect at low doses.
5
Q
What are adverse effects of thiazides? What populations respond well to thiazides?
A
- mild hypokalemia: can be reversed with combing with potassium sparing diuretic or supplements.
- hypomagnesia. important for Na/K ATPase. reversed with supplements.
- cause increased blood levels of uric acid (->gout), cholesterol, TGs, and glucose.
- impotence
- low doses minimizes side effects, except for impotence
- works well with African Americans and elderly. Not as well with young and Caucasian.
6
Q
How do ACE inhibitors lower bp? What are the side effects of ACE inhibitors?
A
- blocks conversion of angiotensin I to II. Decreases aldosterone so Na and water not reabsorbed. Also decreasing angiotensin II decreases vasoconstriction in arteries.
- side effects: cough because of buildup of bradykinin in lungs and hyperkalemia
- Young individuals and Caucasians do better with ACE inhibitors
7
Q
How do Ca blockers work for decreasing HTN?
A
- arteriole dilation and suppression of inotropic and chronotropic actions of myocardium
- they work effectively for African Americans, Caucasians, young and old patients
8
Q
What are two vasodilators? how do they work?
A
- Hydralazine -mechanism unknown
- Minoxidil-opens K channels and causes efflux, which hyper polarizes the SMC and causes relaxation. Only arteriole vasodilation. AKA rogaine
9
Q
What are side effects of Minoxidil?
A
- renal perfusion pressure drops, stimulation of cardiac center to send adrenergic input to kidneys to constrict vessels and retain Na and water.
- cardiac reflex to stimulate heart to increase chronotropic and inotropic effects and angiotensin causing vasoconstriction
- helps to combine with beta blocker
- unwanted hair growth-hypertrichosis
10
Q
Side effects of hydralazine?
A
- triggers lupus like syndrome
- cardiac reflex
11
Q
What are the first line treatments you would used based on population?
A
- Elderly and African Americans: diuretics, Ca channel blockers
- young and caucasian: beta blockers, ACE inhibitors, Ca channel blockers
