Pharmacology session 5:

Pharmacology notes for the cardiovascular system and shock, a few of these topics have been covered before but are seen at a different angle here. This is also the second lecture of the test two material. Happy studying!

-Peter

Cardiovascular 2

tachycardia – fast arrhythmia

Bradycardia – slow arrhythmia

  • treat w/ pacemaker w/out drugs

dys- and arrhythmia are the same for our use

Antidysrhythmic drug classes or group (listen to heart for 1 min)

  • I – quck Na channel blockers (broken up into three classes, but do not need to know that for the test
  • II – Beta Blockers
  • III – K channel blockers
  • IV – Ca channel blockers

Group IA – Sodium channel blockers (fast)

  • quinidine (from cinchona tree bark)
    • Stabilize cell membranes, no Na in
    • ↓ dromotrope
      • SA and AV conduction is slowed (delays REpolarization)
    • for prophylaxis of supraventricular rhythms after Afib, also can control the rate of Vtach
    • Side effects are wide QRS, long QT, AV block, sinus rhythm arrest
      • Confusion, tinnitus, vision issues, Diarrhea, bitter taste in the mouth
    • Nursing monitoring points: Low therapeutic range ECG for QRS and QT length, Dioxin levels, Heart block, Hypotension
    • need to know:
  • Procanimide – causes a lot of side effects but is similar

Group IB Na channel blockers

  • lidocaine (Xylocaine)
    • ↓ depol of mm contraction (decreases the time of action potential)
      • monitor on EKG
    • works first on the tissues with the issues
    • for Ventricular dysrhythmias acutely  
    • narrow therapeutic range
      • the maximum dose is 3mg/kg
    • Side effects – CARDIAC ARREST, confusion, tremors, twitching, blurry vision, tinnitus, dizziness, fainting, Bradycardia
    • D/D interactions with propranolol and cimetidine increase the drug levels

Group IC Sodium channel blockers

  • Flecainide (Tambocor)
    • Very rare
    • Supressess PVS
    • V Dysrhythmias

Group II Beta blockers

  • propranolol(only one that is not beta 1 selective), acebutolol, esmolol, sotalol
    • Decreases contractility, automaticity in SA, and slows conduction
    • cardioprotective for post MI and HF? this is now uncertain, and may not be true
  • propranolol
    • slows conduction, HR, renin, BP,
    • increases cardiac output

Group III K channel blockers: delay repolarization

    • Amiodrarone
      • delays ventricular repol at qt
      • prolongs action potential
      • increases effective refractory period
  • Pulmonary toxicity
  • grapefruit interaction
    • Side effects: thyroid issues, blue grey skin,
    • D/D interactions: increase effect Digoxin, anticoags, statins, dilantin
      • life threatening dysrhythmias

Group IV CC blockers

  • Verapamil (Calan)
    • Decrease contractility and automaticity
    • for afib and flutter vfib, angina
    • important Side effects: edema

other

    • adenosine (Adenocard)
      • slows AV node conduction
  • for PSVT Paroxysmal supraventricular tachycardia
    • rate of delivery is over 3 seconds by an MD, Very unique

Atropine

  • anticholinergic
    • blocks vagal stimulation
      • increase sympathetic nervous system (HR)

antihyperlipidemic

  • metabolic disorder and atherosclerosis

inflamation

  • C-reactive protein levels reflect this
    • high levels associated w/ increased risk of CV problems

Lifestyle modifications first before medication

  • reduce all fats and calories, alcohol, smoking, refined sugars
  • increase exercise

Antilipemic (anti cholesterol) drugs

    • Bile acid sequestrants
      • Colesevelam (Welchol)
        • binds bile acid so it cannot reabsorb
        • does not decrease vitamin absorption and not many other meds
        • Not absorbed
        • for hyperlipidemia and high LDL
        • take with lots of fluids
      • cholestyramine (Questran)
        • Binds bile so it cannot be reabsorbed
        • used with statins
        • take with lots of fluids
    • GI absorption Blockers
      • Ezetimibe (Zetia)
        • Block absorption
        • can take with statin
          • lowers cholesterol by 72%
          • alone 30%
    • Nicotinic Acid Derivatives
      • Niacin
        • increase risk of stroke
    • Cholesterol synthesis inhibitors
      • Lovastatin (Mevacor)
      • HMG-CoA reductase inhibitors
        • for hyperlipidemia when diet is not enough
        • Side effects: MYALGIA, can lead to mm damage, Kidney injury
          • more risky when taken w/ niacin or gemfibrozil
        • Grapefruit interaction, increase the level of the med
  • Not all statins are alike
      • least impactful to most impactful
        • Lova-, Prava-, Simva-, Atorva-, Rosuva-
        • rosuvastatin newest, strongest, most side effects
        • HDL changes start at simvastatin
  • Fibrates (for triglycerides)
    • gemfibrozil (Lopid)
      • inhibits synthesis of VLDL (carrier of triglycerides)
  • Omega-3 fatty Acids
    • Fish oil
    • RX is Lovaza
    • not complete evidence in: dementia, Diabetes

Antianginals All these are IMPORTANT

    • Angina – chest pain, not enough O2 for the heart
      • chronic stable is pain on exertion
      • chronic unstable is pain at random
      • chronic
        • need to control pain quickly, increase MvO2 and/or decrease demand
    • Organic Nitrate Vasodilators
      • nitroglycerin
        • both short and long term
        • vasodilates peripheral and coronary arteries
          • does not dilate the atherosclerotic vessels (so the elderly may not respond well)
          • Hypotension Fall risk
          • will get a headache and that’s OK
          • taken sublingual(minutes), ointment (half hour to hour and can cause tolerance)
        • wear gloves when applying the patch to avoid headache
  • Use for chest pain emergency
          • one SL wait 5mins
          • if after second dose pain is still happening call 911
          • take no more than 3 doses
        • Capsules
          • sustained release
        • Ointment
          • apply to hairless chest wall and cover with plastic
        • transdermal patch
          • don’t soak in water
  • rotate placement
  • 10-12 hr time w/out patch
      • D/D interactions: any hypertension meds
        • nicotine
        • Phosphodiesterase
      • Light and heat will break down the drug and make it ineffective
  • Others for chronic angina
    • Beta blockers
      • reduces heart rate and force of contraction and therefore O2 demand
      • long term only
      • makes vasospastic angina worse (prinzmetal)
    • Calcium channel blockers
      • used in stable vasospastic angina

Shock

Dopamine

  • catecholamine (sympathomimetic)
    • increase BP, CO, vasoconstriction (B1, A2)
    • Very toxic to tissues
    • need large bore IV
    • For Cardiogenic shock primarily and vasoconstriction (neurogenic shock)

DOBUTamine

  • Beta 1 only
    • increases HR, no vasoconstriction
    • For Cardiogenic shock

Epinephrine

  • catecholamine (sympathomimetic)
    • A1, vaso constriction
    • increase BP
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