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Drugs used to treat Hypertension

Drugs used to treat Hypertension. HTN = BP > 140/90 Assos. With: premature death vascular disease of brain, heart,kidneys. Goal of treatment. Prolong useful life by preventing cardiovascular problems by reducing BP < 140/90. Blood Pressure. Review of physiology

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Drugs used to treat Hypertension

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  1. Drugs used to treat Hypertension • HTN = BP > 140/90 • Assos. With: premature death vascular disease of brain, heart,kidneys

  2. Goal of treatment • Prolong useful life by preventing cardiovascular problems by reducing BP < 140/90

  3. Blood Pressure • Review of physiology • BP caused by: _________ • Systolic pressure: __________ • Diastolic pressure: __________

  4. Blood Pressure • Primary Factors • Cardiac output • Peripheral resistance • Blood Volume

  5. Initial tx. of hypertension • Lifestyle modification first • No smoking • Weight control • Reduce alcohol intake • Decrease stress • Sodium control

  6. Treatment of hypertension • Lifestyle modification first • Initial tx. drug- diuretic or B-blocker • Low dose first, increase dose if necessary • 2nd med. if needed • Most respond with diuretic and one other medication (stepped care) • Tx pump, fluid volume, or PVR

  7. Drugs to treat hypertension • 5 primary classes • Diuretics • Calcium channel blockers • Angiotesin converting enzyme (ACE) inhibitors • Autonomic nervous system agents • Direct acting vasodilators

  8. Diuretics • Tx: mild to moderate HTN • First drug of tx. • Also tx. heart failure or kidney disease • Few adverse side effects • Used with other antihypertensives to enhance effectiveness

  9. DiureticsAction • Reduce blood volume through urinary excretion of water and electrolytes • Electrolyte imbalances can occur (mainly hypokalemia) • Depends on type of diuretic

  10. Diuretics • Most efficient: Loop or High-ceiling • Reduce edema assos. with CHF • Increase UO even if blood flow to kidney is diminished • Hypokalemia • KCL supplement given • Lasix, Demadex, Bumex

  11. Diuretics • Most widely prescribed: Thiazides • Mild to moderate HTN-primarily • Hydrodiuril – hydrochlorothiazide (HCTZ) • Hypokalemia • Potassium supplement- KCL

  12. Diuretics • Potassium-sparing:prevent hypokalemia • Mild HTN • Used in combination with other diuretics • No supplement taken • Watch for hyperkalemia

  13. Side effects • Orthostatic hypotension • Dry mouth,irritation Report: • Electrolyte imbalance- hypokalemia (potasium<3.5) • Disorientation • dehydration

  14. Implications for use • Optimal time to admin.= AM • Check VS • Accurate intake and output • Daily weights • Monitor electrolyte imbalances

  15. Calcium Channel Blockers • Emerged as major drug to tx. HTN • Used for arrythmias also • Alternative to B-blocker (hx. Asthma)

  16. Calcium Channel Blockers Action: blocks ca+ access to muscle cells contractility + conductivity of the ______________________ demand for oxygen PVR (relaxing arterioles)

  17. Calcium Channel Blockers Examples • Verapamil Very • Procardia (nifedipine)-HTN Nice • Cardizem (diltiazem)-arrythmias Drugs

  18. Calcium Channel Blockers • SIDE EFFECTS • BP • Bradycardia • May precipitate A-V block • Headache • Abdominal discomfort • Peripheral edema

  19. Angiotensin-Converting Enzyme Inhibitors • “ACE” inhibitors • Mainstay of oral vasodilator therapy • Major breakthrough in tx. of HTN • More effective when used with diuretics

  20. ACE INHIBITORS Angiotensin Converting Enzyme (ends in PRIL) captopril enalapril benzapril (Capoten) (Vasotec) (Lotensin)

  21. RENIN-ANGIOTENSIN-ALDOSTERONE AXN. • BP • excrete renin • formation of angiotensin I • angiotensin II = potent vasodilator • Aldosterone release Na and H2O

  22. ACE INHIBITORS • ACTION • peripheral vascular resistanse without Ø cardiac output Ø cardiac rate Ø cardiac contractility

  23. Advantages • Infrequent orthostatic hypotension • Lack of aggravation of pulmonary dx. • Lack of aggravation with DM • Increase renal blood flow

  24. Side effects • Headache • Orthostatic hypotension-infrequent • Cough • GI distress

  25. Drug interactions • Diuretics • Alcohol • Beta-blockers • All the above enhance the effects

  26. Adrenergic ReceptorsReview of ANS • Sympathetic Nervous System • Alpha 1 = vasoconstriction • Alpha 2 = feedback/vasodilation • Beta 1 = increases heart rate • Beta 2 = bronchodilation

  27. Beta Adrenergic Blocking Agents • Known as Beta-blockers • Axn: Inhibit cardiac response to sympathetic nerve stimulation by blocking Beta receptors • Decreases heart rate and C.O. • Decreases blood pressure

  28. Beta Adrenergic Blocking Agents • Examples – “olol” names • Beta 1: Atenolol • Beta 1 and 2: Propranolol

  29. Nursing Implications • Can not be abruptly discontinued • Check baseline b.p. • Check hx. of resp. condition-aggravates bronchoconstriction

  30. Side effects • Bradycardia • Bronchospasm, wheezing • Diabetic: hypoglycemia • Heart failure: edema,dyspnea,rhales

  31. Interactions • Antihypertensives- additive effect • B-adrenergic agents- inhibit axn. • Enzyme inducing agents-enhance metabolism • Indomethacin and salicylates:< controll

  32. Alpha-1 adrenergic blockers • Alternative if B-blockers and diuretics do not work • Also used to tx. mild to mod. urinary obstructive dx. (BPH)

  33. Alpha-1 Adrenergic Blocking Agents Action: • Block postsynaptic alpha-1 adrenergic receptors to produce arteriolar and venous vasodilation • Reduces peripheral-vascular resistance

  34. Side effects • Drowsiness • Headache • Dizziness,tachycardia,fainting • Weakness,lethargy • Interactions: other antihypertensives (enhance effects)

  35. Clinical Implications • Side effects most prevalent with first dose • Warn pt. that this is nl. • Instruct pt. to lie down if dizzy,weak,etc.

  36. Examples of Apha-1 blockers • Cardura (doxizosin) • Minipress (prazosin) • Hytrin (terazosin)

  37. Centrally Acting Alpha-2 Agonists • Stimulate Alpha-2 receptors in brainstem • Decreases HR, SBP and DBP • More frequent side effects – drowsiness, dry mouth, dizziness • Never suddenly DC = rebound HTN • Clonidine – Catapres ( available in TTS) • Methyldopa - Aldomet

  38. Direct Acting Vasodilators • Action: dirct arteriolar smooth muscle relaxation, decreasing PVR • Uses: HTN, renal dx., toxemia of pregnancy • Ex: Apresoline, Minoxidel • SE: tachycardia, orthostatic hypotension,dizziness, palpitations, nausea, nasal congestion

  39. Client Teaching forAntihypertensive drugs • Take medication as prescribed • Never discontinue without approval of healthcare provider • Incorporate lifestyle changes, even if medication brings BP within nl. Limits • Check BP on regular basis and report significant variations (and pulse) • Get out of bed slowly

  40. Client Teaching forAntihypertensive drugs • Increase intake of potassium-rich foods, unless taking potassium sparing diuretics • Weigh regularly and report abnormal weight gains or losses • Do not take OTC drugs without checking with healthcare provider

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