Drugs Affecting the Cardiovascular System

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• Drugs Affecting the Cardiovascular System

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Cardiovascular System

• Muscular organ with 4 chambers
• Pumps 5-6 liters blood/minute

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Chambers of the Heart

• Left Side
• Oxygenated
• Pulmonary veins
• Atrium
• Mitral valve
• Ventricle

• Right Side
• Unoxygenated
• Atrium
• Tricuspid valve
• Ventricle
• Pulmonary arteries

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Systole and Diastole

• Systole Heart is contracting
• Diastole Heart is relaxed

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Renin-Angiotensin-Aldosterone

• Renal blood flow decreased
• Sympathetic stimulation causes release of renin
• Renin plasma angiotensin forms angiotensin I
• Angiotensin I converted in lungs to angiotensin II

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Renin-Angiotensin-AldosteroneContinued

• Agniotensin II Produces
  vasoconstriction Acts directly on kidney to
  retain sodium water Stimulates
  adrenal cortex to secrete aldosterone

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Cardiotonic-Inotropic Effects

• Increase force of myocardial contraction
• Causes improved hearts pumping ability

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Cardiotonic-Inotropic Drugs

• Adrenergic
• Digitalis glycosides
• Amrinone
• Milrinone

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Inotropic Definition

• Force of myocardial contraction
• Positive inotropic drug increases force of
  contractions
• Negative inotropic drug decreases force of
  contraction

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Digitalis Glycosides

• Increase myocardial contractility causing more
  complete emptying

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Digitalis Glycosides

• Digitoxin
• Absorption
• 90-100 Oral

• Digoxin
• Absorption
• 60-80 Tablet
• 90-100 Capsule
• 70-85 Elixir

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Digitalis Glycosides Continued

• Digitoxin
• Distribution
• To most body tissues
• 90 bound to albumin

• Digoxin
• Distribution
• Throughout the body
• Binds to skeletal muscle/20-30 to albumin

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Digitalis Glycosides Continued

• Digitoxin
• Metabolism
• Liver - 8 converted to digoxin
• Excretion
• Kidneys

• Digoxin
• Metabolism
• Small amount in liver GI flora
• Excretion
• Unchanged drug from kidneys

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Antianginal Drugs

• Organic nitrates produce vasodilation
• Beta-adrenergic blocking drugs Inhibits
  sympathetic stimulation
• Calcium-channel blockers Prevents Ca moving into
  cells

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Antihypertensive Drugs

• Diuretics
• Antiadrenergics
• ACE inhibitors
• Calcium-channel blockers

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Hypotension and Shock

• Alpha-adrenergic drugs increase peripheral
  vascular resistance
• Beta-adrenergic drugs increase myocardial
  contractility heart rate