The document discusses the cardiovascular system and drugs that affect blood pressure. It covers the heart and circulation, factors that determine heart oxygen use and blood pressure, hypertension treatment approaches, and classes of antihypertensive drugs like diuretics, beta-blockers, calcium channel blockers, ACE inhibitors, vasodilators, and drugs that treat hypotension. It also briefly mentions cardiotonic drugs.

1. THE CARDIOVASCULAR SYSTEM Nhelia B. Perez RN, MSN Northeastern College Santiago City

2. INTRODUCTION The Heart The Cardiac Cycle Conduction System of the heart

5. THE CARDIOVASCULAR SYSTEM Circulation 1. Pulmonary and systemic circulation 2. arteries, capillaries and veins 3. coronary circulation

6. Main Forces that determine the heart’s use of oxygen or oxygen consumption Heart rate Preload Afterload Stretch on the ventricles

7. Systemic arterial pressure Venous pressure

8. DRUGS AFFECTING BLOOD PRESSURE

9. Three elements which determines the pressure in the Cardiovascular System Heart Rate Stroke Volume Total Peripheral Resistance

10. Baroreceptors Renin-Angiotensin System Hypertension Hypotension

12. Anti hypertensive agents STEPPED-CARE APPROACH TO TREATING HYPERTENSION 1. Lifestyle modifications 2. drug therapy 3. combination effect 4. steps 1,2 and 3 plus more anti hypertensive agents.

13. DIURETICS Drugs that increase the excretion of sodium and water from the kidney

14. Sympathetic Nervous System Blockers Beta-blockers block vasoconstriction, decrease heart rate, decrease heart rate, decrease cardiac muscle contraction and tend to increase blood flow to the kidneys leading to a decrease in the release of renin.

15. Alpha and beta-blockers are useful in conjunction with other agents and tend to be somewhat more powerful, blocking all of the receptors in the symphatetic system.

16. Alpha-adrenergic blockers inhibit the postsynaptic alpha-adrenergic receptors, decreasing symphatetic tone in the vasculature and causing vasodilation which leads to a lowering of BP.

17. Alpha-blockers are used to treat hypertension because of their ability to block the postsynaptic alpha-receptor sites.

18. Alpha Agonists stimulate the alpha receptors in the central nervous system and inhibit the cardio-vascular centers, leading to a decrease in symphatetic outflow from the CNS and a resultant drop in blood pressure.

19. Angiotensin – Converting Enzyme Inhibitors Blocks the conversion of angiotensin I to angiotensin II in the lungs. This prevents release of aldosterone. Captopril, Moexipril

20. Calcium Channel blockers Calcium channel blockers are a class of drugs and natural substances which disrupt the conduction of calcium channels . The main clinical usage of calcium channel blockers is to decrease blood pressure . It is for this action that they are used in individuals with hypertension .

21. Most calcium channel blockers decrease the force of contraction of the myocardium (muscle of the heart). This is known as the negative inotropic effect of calcium channel blockers. It is because of the negative inotropic effects of most calcium channel blockers that they are avoided (or used with caution) in individuals with cardiomyopathy . Many calcium channel blockers also slow down the conduction of electrical activity within the heart, by blocking the calcium channel during the plateau phase of the action potential of the heart Amlodipine, Diltiazem, Felodipine, Nicardepine, Nifedepine, Verapamil

22. Vasodilators These medicines work by relaxing the smooth muscle of blood vessels, which opens up (dilates) the blood vessels. This allows blood to flow more easily, thereby lowering blood pressure. Hydralazine

23. Antihypotensive Agents Sympathetic Adrenergic Agonists works by acting on the sympathetic adrenergic receptors to cause the effects of sympathetic stress response.

24. CARDIOTONIC DRUGS