Drugs Affecting the Drugs Affecting the Cardiovascular SystemCardiovascular System

Cardiovascular System Cardiovascular System

Muscular organ with 4 chambersMuscular organ with 4 chambersPumps 5-6 liters blood/minutePumps 5-6 liters blood/minute

Chambers of the HeartChambers of the Heart

Left SideLeft SideOxygenatedOxygenated Pulmonary Pulmonary

veinsveinsAtriumAtriumMitral valveMitral valveVentricleVentricle

Right SideRight Side Unoxygenated Unoxygenated AtriumAtriumTricuspid valveTricuspid valveVentricleVentriclePulmonary Pulmonary

arteriesarteries

Systole and DiastoleSystole and Diastole

Systole: Heart is contractingSystole: Heart is contracting Diastole: Heart is relaxedDiastole: Heart is relaxed

Renin-Angiotensin-AldosteroneRenin-Angiotensin-Aldosterone

Renal blood flow decreasedRenal blood flow decreasedSympathetic stimulation causes Sympathetic stimulation causes

release of reninrelease of reninRenin + plasma angiotensin Renin + plasma angiotensin

forms angiotensin Iforms angiotensin IAngiotensin I converted in lungs Angiotensin I converted in lungs

to angiotensin IIto angiotensin II

Renin-Angiotensin-AldosteroneRenin-Angiotensin-AldosteroneContinuedContinued

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

Cardiotonic-Inotropic EffectsCardiotonic-Inotropic Effects

Increase force of myocardial Increase force of myocardial contractioncontraction

Causes improved heart’s Causes improved heart’s pumping abilitypumping ability

Cardiotonic-Inotropic DrugsCardiotonic-Inotropic Drugs

AdrenergicAdrenergic Digitalis glycosidesDigitalis glycosides AmrinoneAmrinone MilrinoneMilrinone

Inotropic DefinitionInotropic Definition

Force of myocardial contractionForce of myocardial contractionPositive inotropic drug: Positive inotropic drug:

increases force of contractionsincreases force of contractionsNegative inotropic drug: Negative inotropic drug:

decreases force of contractiondecreases force of contraction

Digitalis GlycosidesDigitalis Glycosides

Increase myocardial contractility Increase myocardial contractility causing more complete causing more complete emptyingemptying

Digitalis GlycosidesDigitalis Glycosides

DigitoxinDigitoxin

Absorption:Absorption:

90-100% Oral90-100% Oral

DigoxinDigoxin

Absorption:Absorption:

60-80% Tablet60-80% Tablet

90-100% Capsule90-100% Capsule

70-85% Elixir70-85% Elixir

Digitalis Glycosides Digitalis Glycosides ContinuedContinued

DigitoxinDigitoxin

Distribution:Distribution:

To most body To most body tissuestissues

90% bound to 90% bound to albuminalbumin

DigoxinDigoxin

Distribution:Distribution:

Throughout the Throughout the bodybody

Binds to skeletal Binds to skeletal muscle/20-30% muscle/20-30% to albuminto albumin

Digitalis Glycosides Digitalis Glycosides ContinuedContinued

DigitoxinDigitoxin

Metabolism:Metabolism:

Liver - 8% Liver - 8% converted to converted to digoxindigoxin

Excretion:Excretion:

KidneysKidneys

DigoxinDigoxin

Metabolism:Metabolism:

Small amount in Small amount in liver & GI floraliver & GI flora

Excretion:Excretion:

Unchanged drug Unchanged drug from kidneysfrom kidneys

Antianginal DrugsAntianginal Drugs

Organic nitrates: produce Organic nitrates: produce vasodilationvasodilation

Beta-adrenergic blocking drugs: Beta-adrenergic blocking drugs: Inhibits sympathetic stimulationInhibits sympathetic stimulation

Calcium-channel blockers: Calcium-channel blockers: Prevents Ca moving into cellsPrevents Ca moving into cells

Antihypertensive DrugsAntihypertensive Drugs

DiureticsDiureticsAntiadrenergicsAntiadrenergicsACE inhibitors ACE inhibitors Calcium-channel blockersCalcium-channel blockers

Hypotension and ShockHypotension and Shock

Alpha-adrenergic drugs: Alpha-adrenergic drugs: increase peripheral vascular increase peripheral vascular resistanceresistance

Beta-adrenergic drugs: increase Beta-adrenergic drugs: increase myocardial contractility & heart myocardial contractility & heart raterate