Anti-hypertensives Flashcards
Clonidine
centrally acting alpha 2 agonist
MOA: activate alpha 2 receptor–>decrease central sympathetic outflow–>decrease NE release
Effect:–>decrease TPR
Uses:
- HTN
- Clonidine used in withdrawal from abused drugs
Advantages of using:
- No change in lipids
- used in nicotine dependence
Clonidine Toxicities
- dry mouth
- sedation
- rebound HTN
Methyldopa Toxicities
- positive Coombs test (hemolytic anemia)
DOC to treat anti hypertension in pregnancy
Clonidine; also doesn’t cause a change in lipids
Methyldopa
centrally acting alpha 2 agonist
MOA: activate alpha 2 receptor–>decrease central sympathetic outflow–>decrease NE release
Effect:–>decrease TPR
Uses:
1. HTN in pregnancy–DOC
Reserpine
MOA; Effects & Uses
Sympathetic nerve terminal blocker
MOA: blocks vesicular uptake & depletes transmiter stores
Hemodynamic effects: Decrease TPR & CO
Uses: rarely used to treat HTN
Reserpine Toxicities
Toxicities: sedation & depression
Disadvantages/Contraindicated: depression
Guanethidine toxicities & disadvantages/contraindications
Toxicities:
1. Orthostatic Hypotention
2. Fluid retention
Disadvantages/Contraindicated: CHF
Guanethidine MOA, Effects & Uses
Sympathetic nerve terminal blocker
MOA: interferes with amine release & replaces NE in vesicles
Hemodynamic effects: Decrease TPR & CO
Uses: rarely used to treat HTN
Use of Alpha 1 blockers to treat Hypertension
MOA:
- selectively block alpha1A receptors
- reduce prostatic SM tone
Hemodynamic effects: Decrease TPR
Uses: 1. HTN 2. BPH
Toxicities: orthostatic hypertension
Disadvantages/contraindications: none
Advantages: Decreases VLDL & LDL
Alpha 1 blockers used to treat HTN
- prazosin
- terazosin
- doxazosin
Use of Beta blockers to treat Hypertension
MOA:
- Block B1 receptors
- decrease renin secretion
Hemodynamic effects–> Decrease CO
Clinical Uses: 1. HTN 2. HF
Toxicities/interactions: Bronchoconstriction
Contraindication:
- Bronchial asthma
- Heart Block
Advantages: Prolong survival
***labetalol is DOC in pregnancy
Beta Blockers used to treat Hypertension
- metoprolol
- atenolol
- carvedilol (blocks B1 & alpha receptors)
Drugs used to treat HTN that work by decreasing CO
- beta blockers
2. calcium-channel blockers (work by decreasing HR & FOC)
Vasodilators used to treat HTN that work by decreasing systemic vascular resistance
- alpha blockers
- direct-acting vasodilators
- Angtiotensin-converting enzyme inhibitors (ACE inhibitors)
- angiotensin receptor blockers (ARBs)
Antihypertensives that work at the vasomotor center
- methyldopa
- clonidine
- guanabenz
- guanfacine
Antihypertensives that work at sympathetic ganglia
Trimethaphan
Antihypertensives that work at sympathetic nerve terminals
- guanethidine
- guanadrel
- reserpine (not used bc it depletes MO–>depression)
Antihypertensives that work at beta receptors of heart
beta blockers ie propranolol
Antihypertensives that work at angiotensin receptors of vessels
- losartan
2. other angiotensin receptor blockers
Antihypertensives that work at alpha receptors of vessels
- prazosin
2. and other alpha 1 blockers
Antihypertensives that work at vascular smooth muscle
- hydralazine
- minoxidil
- nitroprusside
- diazoxide
- verapamil & other CCB
- Fenoldopam
Antihypertensives that work at kidney tubules
- thiazides, etc
Antihypertensives that work at beta receptors of juxtaglomerular cells that release RENIN
Propranolol & other beta blockers
Angiotensinogen is converted to angiotensin 1 by _____ which is inhibited by _______
- renin
2. alskiren
angiotensin 1 is converted to angiotensin II by _________ which is inhibited by ___________
- Angiotensin-converting enzyme (ACE)
2. Captopril & other ACE inhibitors
How do diuretics treat HTN?
- they reduce venous pressure & CO by reducing blood volume
- HOW? They act on the kidney to enhance Na & water excretion
- Reducing blood volume not only reduces central venous pressure, but also CO!
What group of diuretics are preferred for HTN? WHY? Ex?
Thiazides, bc maximum antihypertensive action is at LOWER doses than the diuretic dose!
Ex) hydrochlorothiazide
Added BONUS: they reduce SVR with long-term use
Loss of Na–>decreased vessel stiffness–>decreased TPR
Toxicity of Thiazides
- hypokalemia
- decrease glucose tolerance and may unmask latent DM
- increase plasma LDL, cholesterol & triglycerides (TG)
- increase plasma uric acid & may precipitate acute gout
MOA for beta blockers as anti-HTN drugs
- decrease in CO by blocking cardiac Beta 1 receptors
2. inhibition of renin release by blocking beta 1 receptors on JG cells
Hemodynamic effects of beta blockers in HTN
a) Decreased:
1. HR
2. CO
3. PVR
b) Unchanged: venous tone
c) Negligable: postural hypotension
all beta blockers are equally effective in lowering BP in??
mild to moderate HTN
in severe HTN, beta blockers are useful???
in preventing the reflex tachycardia that often results from treatment with direct vasodilators
beta blockers have shown to reduce mortality after
MI & heart failure
Propranolol
a) type
b) toxicities
c) prolonged use warning
a) non-selective comound
b)
1. bradycardia or cardiac conduction disease
2. asthma
3. peripheral vascular insufficiency
4. diabetes
c) DO NOT discontinue abruptly after prolonged regular use bc can result in reflex tachycardia
Cardio-selective beta 1 drugs
b) benefits?
- atenolol
- metoprolol
b) cause less bronchoconstriction than propranolol
beat blockers with additional alpha blocking activity
b) when would you use them?
- labetalol
- carvedilol
b) tumor in adrenal medulla (pheochromocytoma)
Calcium channel blockers act on
L type calcium channels
CCB effective in lowering BP
- verapamil
- diltiazem (has intermediate actions)
- DHP (amlodipine, felodipine, isradipine, nicardipine, nifedipine, nisoldipine)
DHP
a) examples
b) selectivity
c) can cause
- amlodipine
- felodipine
- isradipine
- nicardipine
- nifedipine (not for HTN bc too short acting!!)
- nisoldipine
b) more selective as vasodilators
c) can cause slight reflex tachycardia
Verapamil
- has the greatest depressant effect on the heart
- may decrease HR & CO
- How? L-type Ca channels–>decrease FOC
DHP not used for HTN bc too short acting
nifedipine
How do calcium channels lead to muscle contraction?
- calcium comes in
2. binds to myosin light chain kins
Inhibitors of Renin Angiotensin Aldosterone System (RAAS)
- ACE inhibitors: end in “-pril” (captopril, Enalapril, Ramipril, Benazepril, fosinopril, lisinopril, quinapril)
- Angiotensin Receptor Blockers (ARBs): end in “-sartan” (Losartan, Valsartan, Candesartan, sprosartan, irbesartan, telmisartan, olmesartan)
- Renin antagonist: aliskiren
- Aldosterone Receptor inhibitors: end in “-one” (spironolactone, elprenone)
ACE Inhibitors
end in “-pril”
- captopril
- Enalapril
- Ramipril
- Benazepril
- fosinopril
- lisinopril
- quinapril
end in “-pril”
ACE inhibitors