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41 Cards in this Set
- Front
- Back
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what is the general function of Class I Drugs
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Na+ channel blockers
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what is the general function of Class II drugs
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reduce adrenergic activityon the heart
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what is the general function of Class III drugs
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K+ channel blockers
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what is the general function of Class IV drugs
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Ca++ channel blockers
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what is the general function of Class I A drugs
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blocks activated Na+ channels
lengthens the duration of the action potential inc ERP |
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what is the general function of Class I B drugs
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blocks inactivated Na+ channels
shortens the duration of the action potential dec ERP |
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what is the general function of Class I C drugs
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blocks all Na+ channels
No effect on duration of the action potential |
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what is the Class I A drug of choice
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Quinidine
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what is the Class I B drug of choice
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Lidocaine
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what is the Class I C drug of choice
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flecainide
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what are the Class II drugs
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B-blockers
Propranolol |
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what are the Class III drugs
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Amiodarone
Sotalol |
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what is the Class IV drug of choice
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Verapamil
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what are the cardiac effects of quinidine (quinora)
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prolongs the duration of the action potential
thus, dec automaticity M receptor blockade (inc HR) blocks Alpha receptors (vasodilation, poss reflex tachy) Cinchonism- tinitis, vertigo, headache, allergy |
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whar are the pharmokinetics of quinidine (quinora)
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orall
first pass metabo t 1/2- 6 hours |
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what are the toxicitys of Quinidine (quinora)
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low therapeutic index
cardiac toxicity severe hypotension paradoxical Tachy Torsade de pointes digitalis + quinidine = syncope and death diarrhea Cinchonism |
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what are the drug interactions to consider with quinidine
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Q + digitalis= syncope and death
phenytoin decreases Q effectiveness Q inc warfarins effect Q + NTG= extra dec in BP increases the effect of muscle relaxants |
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what extra toxicities does procainamide have over quinidine
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SLE***
arthritis inc ANA titer hepatitis |
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How is disopyramide different from quinidine
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negative inotropic effect
antichilenergic |
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what type of arrhythmias is lidocaine used to treat?
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Ventricular arrhythmias
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lidocaine's mech of action
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binds inactivated Na+ channels
-block of the slow Na+ "window" currents |
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what are the benifits of using Lidocaine over Quinidine (or other Class I A)? Drawbacks?
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benifits:
-less hypotension -does not depress myocardial contractility (least neg inotropic of all antiarrhythmics) -no vagal blocking Drawbacks: -only good for Ventricular arrhythmias -only IV admin (I.E no outpatient) |
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lidocaine toxicities
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convulsion
bradycardia & aggrivation of arrhythmias occasionally |
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what is flecainide used for
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treatment of supraventricular tachy
life threatening ventricular arrhythmias CHF clinicl study for its pro-arrhythmic effects** |
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gen facts about Flecainide
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binds all Na+ channels
no ANS effects orall, hepatic metab & renal excret |
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key points for propafenone (Class I C)
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used for refractory pts c severe, life threatening arrhythmias
B-blocking activity as well |
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what is the mech of action for Amiodarone
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Class III (K+) > Class I, IV activity
alpha blocking effects- vasodilation |
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What is the half life for Amiodarone
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13-103 days
LD-15 to 30 days |
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toxicities associated with Amiodarone
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brady
heart block, heart fail pulmonary fibrosis tissue deposition (yellow-eye, blue-skin) photodermatitis thyroid dysfxn constipation liver toxicity |
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use of Amiodarone
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only approved for Ventricular arrhythmias
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Sotalol (betapace) info
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K+ blocker
nonselective Beta blocker prolonged action potential Oral, renal excre SV arrhy and ventricular arrhythmias Toxicity- Torsades de pointes, B-blockade |
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what are the mech of action and effects of Verapamil
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Ca++ channel blocker (L-type)
dec AV conduction, dec HR most benificial in SVTarrhythmias antihypertensive antianginal |
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pharmokinetics of Vermapimil
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Oral or IV
first pass if oral kidney excretion |
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what are the key toxicities assoc with verapamil
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GI intolerance
bradycardia neg inotropic effect poss AV block (IV) contraindicated in CHF do not use with B-blockers |
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use of verapamil
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reentrant SVT
reduces ventricular rate in aflutter and afib |
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uses of diltiazem
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Prinzmetals angina
angina pectoris HTN following angioplasty |
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what is the mech of action for Adnosine (Adenocard)
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enhanced K+ conductance
inhibit Ca++ influx inhibits AV conduction IV admin |
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toxicities of Adenosine (adenocard)
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Flush, SOB, burning
hypotension, headache, nausea |
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what is the clinical use of Adenosine (adenocard)
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Drug of choice for paroxysmal SVT
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what is Magnesium sulfate used for
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treatment of eclampsia and preeclampsia
digitalis (glycoside) induced arrhythmias torsade de pointe |
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K+ and the heart
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both hypo and hyperkalemia are arrhythmogenic
hypo- risk of afterdepolarization hyper- membrane stabilizing to a point, then lethal arrhythmias |
