Documents
Resources
Learning Center
Upload
Plans & pricing Sign in
Sign Out

Drugs used to treat Hypertension

VIEWS: 181 PAGES: 40

									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
   2nd 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

								
To top