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16 Cards in this Set
- Front
- Back
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혈압 조절 기전 |
a. Baroceptor b. Renal mechanism c. Neuronal mechanism d. Autoregulation |
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고혈압으로 인한 사망 원인 |
a. MI (myocardial infarction)/ CHF (congestive heart failure) b. Stroke |
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Anti-hypertensive agents |
1. Diuretics -Depleting Na -Reducing blood volume -Other mechanisms 2. Sympatholytic agents -Reducing peripheral resistance -Inhibiting cardiac output -Increasing venous pooling 3. Direct vasodilators -Relaxing vascular s.m. -Dilating resistance vessels -Increasing capacitance 4. Agents that block RAAS - Reducing peripheral resistance and blood volume |
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Diuretics |
Early: reducing blood volume and cardiac output Later: reducing peripheral vascular resistance (lowering Ca2+ in v.s.m.) - Major effect: decrease Na+ in interstitial space of vascular s.m. - decrease Ca2+ influx
- Minor effect: K-channel opening of v.s.m. - hyperpolarization |
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Thiazide |
•Normally used in mild or moderate hypertension with normal renal and cardiac function •Low dose alone or with K-sparing agents/ ACE inhibitor or ARBs - If not effective, better add a second drug rather than increase dose
•Toxicity -K loss (hypokalemia) : common in diuretics -Digitalis toxicity in patients with chronic arrhythmia, acute MI, or left ventricular dysfunction -Hyperuricemia (Gout by uric acid retention) -Electrolyte imbalance (low Na+, high Ca2+): epi cell 의 입장. -LDL elevation -Erectile dysfunction |
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Loop Diuretics |
Low Ca2+ 이 문제다. |
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#1. Sympatholytic agents-centrally acting |
-causes compensatory retention of Na+ by the kidney. -Most effective when used with diuretics.
eg) methyldopa (m-DOPA): -agonist of presynaptic a2 in brain stem -> prevention of LV hypertrophy -renin/angiotensin reflex 가 있을 수 있다.
eg2) Clonidine -withdrawal may cause fatal hypertensive crisis (rebound HT) |
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Centrally acting agents toxicity |
a. Dry mouth (xerostomia) b. Cardiac effect: bradycardia c. Hyperprolactinemia: gynecomastia, galactorrhea
Clinical Use: hypertension during pregnancy. |
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#2. Sympatholytic agents -neuron blocking |
eg) Guanadrel: uptake like NE (NET) Reserpine: interferes the transport of biogenic amines
Toxicity: Guanadrel -too polar to enter CNS : less CNS toxicity
Reserpine -readily enter CNS :CNS amine depletion (sedation, depression)
Both -Cardiac effect : bradycardia, sinus arrest -Increased parasympathetic in GI: diarrhea
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#3. Adrenoreceptor antagonist - b adrenergic blocking |
eg) propranolol, atenolol
Mechanism: 1) Reduce contractility, cardiac output in heart 2) Reduce renin secretion in kidney
Side effects: - Bradycardia or cardiac conduction disease Bronchospasm (asthma) Rebound symptom Alpha stimulation in vascular s.m. |
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#4. a1-adrenergic blocking |
a1 blocker = Prazosin Effect: a.Artery, Vein vasodilation - continuous effect b.Reflex tachycardia, Renin reflex - transient effect
Side effect: a.Renin reflex: sodium and water retention b.Postural hypotension within 90 min after first administration c.Reduce TG and LDL but increase HDL
Clinical Use: a. not used alone, but in combination with diuretics, b-blockers, or others b. not be combined with vasodilators (e.g. dihydropyridines): tarchycardia c. good for HT patients with benign prostatic hyperplasia
cf) combined a1, b adrenergic blocking: labetalol, carvedilol |
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Vasodilators |
Hydralazine and minoxidil - Oral vasodilator for long-term outpatient therapy of hypertension
Nitroprusside and diazoxide - Parenteral vasodilators to treat hypertensive emergencies
Calcium channel blockers - used in both
Vasodilators work best in combination with drugs that oppose the compensatory response!
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Sodium Nitroprusside |
a. BP 감소 (치명적 고혈압 또는 surgical bleeding이 있을 때 사용) b. Pre/afterload 감소 -aortic dissection -severe CHF -acute MI
부작용: a. mitochondrial inhibition -> lactic acidosis b. hypothyroidism c. Renin 증가 (rebound HT), V/Q mismatching |
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Arterial Dilators (Hydralazine, Minoxidil, Diazoxide)
cf) 참고로 vein이 dilate되는 효과는 덜하다. |
Hydralazine: unknown target – decrease Ca2+ Minoxidil: KATP opening Diazoxide: KATP opening
-Hemodynamic Effects: BP 감소 (체위성 저혈압 x) -sympath. reflex: a. 심박동, 심수축 증가 b. afterload 증가 c. O2 demand 증가 -renin 증가 a. fluid retention b. preload 증가 c. O2 demand 증가 --> Coronary steal 때문에 ischemia 환자에 사용 x. |
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Vasodilator Toxicity |
Hydralazine - immune rxn. Minoxidil - T wave inversion/hypertricosis, hyperglycemia Diazoxide - T wave inversion, hyperglycemia |
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Ca-channel blocking |
artery dilator 로 nifedipine 사용 가능 |
