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 BP caused by: _________ Systolic pressure: __________ Diastolic pressure: __________

Blood Pressure Primary Factors 1. Cardiac output 2. Peripheral resistance 3. Blood Volume

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

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

Drugs to treat hypertension 5 primary classes 1. Diuretics 2. Calcium channel blockers 3. Angiotesin converting enzyme (ACE) inhibitors 4. Autonomic nervous system agents 5. Direct acting vasodilators

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

Diuretics Action Reduce blood volume through urinary excretion of water and electrolytes 1. Electrolyte imbalances can occur (mainly hypokalemia) 2. Depends on type of diuretic

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Side effects Headache Orthostatic hypotension-infrequent Cough GI distress

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

Adrenergic Receptors Review of ANS Sympathetic Nervous System Alpha 1 = vasoconstriction Alpha 2 = feedback/vasodilation Beta 1 = increases heart rate Beta 2 = bronchodilation

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

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

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

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

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

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

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

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

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

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

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

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

Client Teaching for Antihypertensive 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

Client Teaching for Antihypertensive 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