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Drugs that affect the Cardiovascular system

Drugs that affect the Cardiovascular system. Peggy Andrews, Instructor Chemeketa Community College. What about ‘em?. LEAD Drugs. Lidocaine Interferes with sodium channels to block conduction abnormalities Epinephrine Increases heart rate, blood pressure and stimulates liver Atropine

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Drugs that affect the Cardiovascular system

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  1. Drugs that affect the Cardiovascular system Peggy Andrews, Instructor Chemeketa Community College

  2. What about ‘em?

  3. LEAD Drugs • Lidocaine • Interferes with sodium channels to block conduction abnormalities • Epinephrine • Increases heart rate, blood pressure and stimulates liver • Atropine • Blocks actylcholine, speeds heart • Dopamine • Increases contractile force

  4. Let’s Review First • Most drugs treat dysrhythmias • Most prevalent • Tachycardia • Bradycardia • Generated through abnormal impulse formation (automaticity) • OR abnormal conductivity

  5. Dysrhythmias - Most often caused by imbalance between sympathetic and parasympathetic nervous systems

  6. Bradycardia • Excessive parasympathetic stimulation through muscarinic receptors

  7. Tachycardia • Variety of causes • Ischemia, mycoardial infarction, excessive sympathetic stimulation

  8. Develop phase 4 depolarization, generate abnormal impulse • Ectopic foci • Abnormal conduction; • One-way valve

  9. Antidysrhythmics • SODIUM CHANNEL BLOCKERS

  10. What do they do, anyway? • -amide, ester forms of local anesthetics elevate the threshold of electric excitation of the nerve • Enter open, inactive sodium channels • Anesthetic closes the channel, blocking sodium influx • Delays impulse • Decreases action potential • Blocks conduction

  11. Procainamide • Class: antiarrhythmic • Indications • Treatment of ventricular and arial arrhythmias • PACs, PVCs, VT, PAT, post conversion from Af or AF

  12. Action • Decreases myocardial excitability • Slows conduction velocity • Suppresses arrhythmias

  13. Contraindications • Hypersensitivity • Poisonings from tricyclic antidepressants • Caution • MI • CHF • geriatrics

  14. Adverse reactions • Seizures • Asystole • Heart block • Ventricular arrhythmias • Diarrhea

  15. Route & dose • IV, 20-30 mg/min IV until • Dysrhythmia converted • Hypotension • QRS widens > 50% • 17 mg/kg administered • Cardiac Arrest: 100 mg IVP q 5 min. • Infusion: 1 – 4 mg/min (1 gm in 250 ml NS) • How supplied • 10 mg/ml in 100 mg preload

  16. Lidocaine • Class • Antidysrhythmic • Indications • VT, Vf, malignant PVC’s • Action • Decreases ventricular automaticity & excitability • Raises fibrillation threshold • Decreases conduction in ischemic cardiac tissue without affecting normal conduction

  17. Contraindications • Advanced AV block (Mobitz II , 3rd degree blocks • Torsades de pointes • Stokes-Adams syndrome • Precaution: • Heart rate less than 60 • Hepatic disease - reduce by 50% • >70 y/o – reduce by 50%

  18. Side effects • Drowsiness • Dizziness • Confusion • Hypotension • Nausea, vomiting • Dysrhythmias • Respiratory depression • Cardiac arrest

  19. Route & Dosage: • Loading dose of 1 – 1.5 mg/kg IVP q 5 min. Max dose of 3 mg/kg • After perfusion is reestablished, admin. Lidocaine gtt at 2-4 mg/min (start gtt at 1 mg/min if pt > 70 y/o • How supplied • 10 mg/ml in 100 mg preload

  20. Lidocaine is drug of choice for • Most types of drug-induced monomorphic VT or Vf, and for VT, Vf associated with cocaine-induced myocardial ischemia

  21. Antidysrhythmics • Potassium Channel Blockers

  22. Bretylium Tosylate (Bretylol) • Class; antiadysrhythmic • Different from all other antidysrhythmics • Does not suppress automaticity • Has no effect on conduction velocity

  23. Indications • VT, Vf refractory to lidocaine and defibrillation • Recurrent Vf • VT with a pulse that fails to respond to lidocaine or procainamide • Wide complex tachycardias not controlled by lidocaine and adenosine

  24. Action • Causes an initial but transient release of norepinephrine; effect lasts ~ 20 min. • Then inhibits release of norepinephrine and blocks reuptake of norepinehprine, resulting in depletion of norepinephrine. Results in: • Increased fibrillation threshold • Prolonged effective refractory period • Suppression of reentry dysrhythmias

  25. Contraindication and precautions • No contraindications when used for Tx of life-threatening dysrhythmias • Contraindicated in Torsades • Can result in prolonged hypotension in postresuscitation phase • Side effects • Initial transient elevated BP followed by hypotension • Dizziness, syncope • Angina • Bradycardia • If administered by rapid IVP, N/V

  26. Dosage • Vf, pulseless VT: 5 mg/kg IVP • Repeat with 10 mg/kg q 15 min to max dose of 30-35 mg/kg • If conversion, administer bretylium drip at 1-2 mg/min. • How supplied • 50 mg/ml in 10 ml preload

  27. amiodarone (Amrinone, Cordarone) • Class • antiarrhythmic • Indications • recurrent VF, unstable VT • When other therapies are ineffective

  28. Action • Prolongs action potential and refractory period • Slows sinus rate, increases PR, QT intervals • Contraindications • Severe sinus node dysfunction • 2nd and 3rd degree AV block • Precautions • CHF, severe pulmonary or liver disease

  29. Adverse reactions • ARDS, pulmonary fibrosis, CHF, worsening of arrhythmias • Liver function abnormalities • Anorexia, constipation, N/V, ataxia, involuntary movement, paresthesia, periphreal neuropathy, tremors • Bradycardia, hypotension • Dizziness, fatigue, malaise, corneal microdeposits

  30. Route & dosage • Requires large initial loading dose (IV route) to prevent delay in onset action • Must use filter needle • Draw up slowly – Foams!

  31. For VT hemodynamically stable (SBP> 85) • 150 mg IV over 10-30 minutes • 900 mg IV over 24 hrs by infusion • Repeat 150 mg IV bolus for VT • For VT/VF unstable or no BP • 150-300 mg IV bolus • IV infusion (1mg/min) • May repeat bolus

  32. Not water soluble – must use solventPolysorbate 80 • Polysorbate 80 clinical effects: • Decrease heart rate • Depress AV node conduction • Increase atria and ventricularrefractory periods • Available only in glass ampules

  33. How supplied • 50mg/ml in 3-ml ampules

  34. Antidysrhythmics • Calcium Channel Blockers

  35. Verapamil (Isoptin, Calan) • Class • Antianginal, Antiarrhythmic, antihypertensive agent • Indications • Hypertension, angina, Prinzmetal’s angina, Af or AF with rapid ventricular response • Action • Inhibits transport of calcium into myocardial and vascular smooth muscle • Decreases SA and AV conduction

  36. Contraindications • Hypersensitivity • Precautions • Severe hepatic impairment • Adverse reactions, SE • Arrhythmias, CHF

  37. Dosage and route • 5 – 10 mg, IV • How supplied • 2.5 mg/ml in 2 & 4 ml vials, ampules and syringes

  38. diltiazem (Cardizem) • Class • Antianginal, antiarrhythmic, antihypertensive • Indication • Hypertension, angina, SVTs and Af & AF with rapid ventricular response • Action • Inhibits the transport of calcium into myocardial and vascular smooth muscle

  39. Contraindications • Hypersensitivity • Sick sinus syndrome • 2nd or 3rd degree AV block • Precautions • Severe hepatic impairment

  40. Adverse reactions, SE • Arrhythmias • CHF • Peripheral edema • Dosage & route • 0.25 mg/kg • May repeat in 15 minutes with dose of 0.35 mg/kg • Follow with gtt at 10 mg/hr • How supplied • 5 mg/ml in 10 ml vials • 25 mg preloads

  41. Antidysrhythmics • Miscellaneous

  42. Adenosine (Adenocard) • Class • Antiarrhythmic agent • Indication • Conversion of PSVT • As a diagnostic tool to assess myocardial perfusion

  43. Action • Restores normal sinus rhythm by interrupting re-entry pathways in AV node • Slows conduction through AV node • Contraindications • 2nd or 3rd degree block • Precautions • Asthma • Unstable angina

  44. Adverse reactions & side effects • SOB • Facial flushing • Transient arrhythmias • Dosage & route • 6 mg rapid IVP • Repeat in 1 – 2 min. prn at 12 mg rapid IVP • Repeat in 1 – 2 min. prn at 12 mg rapid IVP

  45. How supplied • 6 mg and 12 mg preload syringes or vials • Onset is immediate • Duration is 1 – 2 min • Note: Proximal IV, RAPID bolus, 20 ml flush with arm raised is critical!!

  46. digoxin (Lanoxin) • Class • Antiarrhythmic agent • Cardiotonic and inotropic agent • Indications • CHF • Tachyarrhythmias • Af & AF • PAT

  47. Action • Increases force of myocardial contractility • Prolongs refractory period of AV node • Decreases conductiion through SA and AV nodes • Contraindications • Hypersensitivity • Uncontrolled ventricular arrhythmias • AV block • IHSS

  48. Precautions • Electrolyte abnormalities • Adverse reactions, SE • Dysrhythmias • Fatigue • Blurred, yellow vision • Anorexia, N/V

  49. Dosage & route • 0.6 – 1.0 mg (10-15 mcg/kg) initially • Give additional fractions at 4 – 8 h intervals • Total dose 200 mg • How supplied • 0.25 mg/ml in 1 ml preload

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