#Antihypertensive Drugs

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#Antihypertensive Drugs

  1. 1. Done by B. Mo. Antihypertensive Drugs
  2. 2. Intro **************************************************** Arterial BP Cardiac Output Peripheral Resistance Heart Rate Contractility Filling Pressure Arteriolar Volume Blood Volume Venous Tone Hypertension Systolic Blood Pressure (SBP) Diastolic Blood Pressure (DBP) > 140 mmHg > 90 mmHg
  3. 3. Cont… **************************************************** Categories of Hypertension Normal ( <120 / <80 ) Prehypertension ( 120-139 / 80-89 ) Stage 1 Hypertension ( 140-159 / 90-99 ) Stage 2 Hypertension ( ≥ 160 / ≥ 100 ) Main Complications Congestive Heart Failure Myocardial Infarction Renal Damage Cerebrovascular Accidents
  4. 4. Cont… **************************************************** Types of Hypertension Essential Secondary A disorder of unknown origin affecting the Blood Pressure regulating mechanisms Secondary to other disease processes Environmental Factors Stress Na+ Intake Obesity Smoking
  5. 5. Mechanisms for Controlling BP The kidney Aortic arch & carotid sinuses Place of receptors The baroreceptors in the kidney will activate the Renin-Angiotensin-aldosteron system, which will cause: - Vasoconstriction by angiotensin II - renal sodium reabsorption & blood volume by aldosterone A fall in Blood Pressure causes the baroreceptors to send impulses to the cardiovascular centers which will: Sympathetic & parasympathetic output Mechanism Long-term control Rapid, moment-to-moment regulation Responsible for The kidney The sympathetic NS Mediated By Renin-Angiotensin-aldosteron system Baroreflexes
  6. 7. Treatment Strategies <ul><li>The goal of antihypertensive therapy is to reduce cardiovascular & renal morbidity and mortality. </li></ul><ul><li>Usually we use one drug (thiazide diuretic) unless it is inadequate to control the blood pressure so we add a second drug ( β -blocker) and maybe third (vasodilator) . </li></ul><ul><li>Individualized Care: some people respond better to one class of drug than they do to another: 1) Black patients: respond well to diuretics & Ca++ channel blockers , but β -blocker or ACE inhibitors is less effective. 2) Elderly: respond well to ACE inhibitors & diuretics , while β -blocker & α -antagonists are less tolerated. 3) Concomitant diseases: hypertension may coexist with other diseases that can be aggravated by the drugs (f 19.4) . </li></ul>
  7. 9. Cont… <ul><li>Patient Compliance: </li></ul><ul><li>- Lack of patient compliance is the most common reason for failure of </li></ul><ul><li>antihypertensive therapy. </li></ul><ul><li>- Therapy is generally to prevent the disease rather than to relieving the </li></ul><ul><li>patient’s discomfort. </li></ul><ul><li>- The main adverse affect between middle-aged & elderly men is </li></ul><ul><li>decreasing the libido and inducing impotence . </li></ul>
  8. 10. Diuretics <ul><li>Recommended as the first-line drug therapy for hypertension. </li></ul><ul><li>Diuretics are superior to β -blockers in older adults. </li></ul>Used in patients with inadequate kidney function Renal vascular resistance Renal blood flow Diuretics Thiazide Loop [Ca++] in urine [Ca++] in urine
  9. 11. Thiazide Diuretics <ul><li>Example: hydrochlorothiazide . </li></ul><ul><li>Action: - lower BP by increasing Na+ & water excretion . - Spironolactone is often used with thiazides because it has the additional benefit of diminishing the cardiac remodelation. </li></ul><ul><li>Therapeutic uses: - decrease BP in both supine & standing position. (postural hypotension is rarely observed except in elderly) - Useful in combination with other antihypertensive drugs that cause water & Na+ retention. - Useful: black & elderly. Not useful: patients with inadequate kidney function. </li></ul>
  10. 12. Cont… <ul><li>Pharmacokinetics: - orally active. - absorption & elimination rates vary . - may compete with uric acid for elimination. (ligands for the organic acid secretory system of the nephron) </li></ul>K+ levels should be monitored in patients predisposed to cardiac arrhythmias Adverse Effects Hypokalemia ( 70% ) Hyperuricemia ( 70% ) Hyperglycemia ( 10% ) Hypomagnesemia
  11. 13. Done by B. Mo. THANX,,, BYE BYE :)

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