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NAPLEX > Arrhythmias > Flashcards

Arrhythmias Flashcards

0
Q

QT prolongation and torsades

A

QT prolongation can lead to torsades, a lethal ventricular tachyarrhythmia which is most commonly associated w/ drugs and can result in sudden cardiac death

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1
Q

Two types of arrhythmias

A
  1. Supraventricular: originating above the AV node
    * example: sinus tachycardia, atrial fibrillation, atrial flutter, focal atrial tachycardia and superventricular reentrant tachycardia
  2. Ventricular: originating below the AV node
    * example: PVCs, ventricular tachycardia and V fib
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2
Q

Things known to prolong the QT interval

A
  1. Pre-existing cardiac condition or history of arrhythmia
  2. Class IA and class III antiarrhythmics (amiodarone, disopyramide, dofetilide, Dronrdarone, ibutilide, procainamide, quinidine, sotalol, Flecainide)
  3. Antibiotics: quinolones, macrolides, Bactrim, amantadine, foscarnet
  4. Azole antifungal’s particularly voriconazole
  5. Chemo and protease inhibitors
  6. Antidepressants: try cyclic’s, SSRIs (particularly Celexa and Lexapro) and trazodone (SERTRALINE IS PREFERRED AND CARDIAC PATIENTS)
  7. Antiemetic agents including serotonin receptor antagonist
  8. Antipsychotics (chlorpromazine, haldol, ziprasidone, risperidone, clozapine, quetiapine
  9. Methadone, droperadol, ranolazine , chloroquine, quinine
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3
Q

Pharmacologic treatment options

A
  1. Prior to starting any antiarrhythmic be sure to always check the patient’s electrolytes and run a toxicology screen
  2. Terminate the arrhythmia and restore and maintain normal sinus rhythm: class I and III
  3. Slow the ventricular rate during a supraventricular arrhythmia: class II AND IV
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4
Q

Vaughan Williams classification of antiarrhythmics

A

Ia: quinidine, procainamide, disopyramide (QT RISK)
Ib: lidocaine, mexiletine, and phenytoin
Ic: flecainide, propafenone
II: beta blockers esmolol and propanolol
III: amiodarone, dofetilide, dronedarone, ibutilide, sotalol (QT risk)
IV: verapamil, diltiazem

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5
Q

Class I antiarrhythmics

A

MOA: sodium channel blockers

Sub classified based on the duration of time they bind the sodium channel Ia are intermediate, IB are fast and Ic are long

Cast trial lead to blackbox warning for elevated mortality in class Ic

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6
Q

Class Ia antiarrhthmics

A

MOA: decrease conduction velocity, increased refractory period, and decrease automaticity

DRUGS: quinidine, procainamide, disopyramide (Norpace)

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7
Q

Quinidine

A

Take with food or milk to dec GI upset

Blackbox warning: may increase mortality in the treatment of a fib or flutter; control AV conduction before initiating (typically with digoxin)

Contraindication: concurrent use of quinolones that prolong the QT interval; second or third degree heart block, thrombocytopenia, TPP

Side effects: major G.I., diarrhea, stomach cramping, QT prolongation, nausea/vomiting, anorexia, lightheadedness, tendinitis, headache, thrombocytopenia and may present a positive Coombs’ test

Note: avoid changes and sodium intake as it can change quinidine levels

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8
Q

Procainamide

A

Has active metabolite which is renally cleared

Blackbox warning: fatal blood dyscrasia, drug-induced lupus, increased mortality

Contraindication: second/third degree heart block, SLP, torsades

Side effects: hypertension, rash, lupus like syndrome, QT prolongation, agranulocytosis

Monitoring: ECG, electrolytes, blood pressure, renal function, signs of lupus, procainamide and NAPA levels

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9
Q

Disopyramide (Norpace)

A

Blackbox warning: class I affect of increased mortality due to CAST trial

Contraindications: second or third degree heart block, cardiogenic shock, congenital QT syndrome, sick sinus syndrome, BPH, narrow angle glaucoma, myasthenia gravis

Side effects: ANTI-CHOLINERGIC, hypotension, QT prolongation, heart failure exacerbation

Monitoring: ECG, electrolytes, blood pressure, signs of heart failure

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10
Q

Class Ib antiarrhythmics

A

Pure sodium channel blockers

Only useful for ventricular arrhythmias not useful for atrial fibrillation

They can all cross the blood brain barrier and therefore can call CNS adverse effects

Decrease conduction at higher heart rates, little effect on refractory period, & decrease automaticity

Drug: lidocaine, mexiletine

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11
Q

Lidocaine (Xylocaine)

A

IV, patch (on 12 off 12 due to risk of arrhythmia)

Contraindications: second or third degree heart block, Wolff-Parkinson-White syndrome, Adam Stokes syndrome, allergy to corn or corn related products

Side effects: lightheadedness, dizziness, incoordination, nausea/vomiting, tremor, CNS effects such as hallucinations, disorientation and confusion

Notes: caution in patients with severe hepatic dysfunction and elderly

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12
Q

Clas Ic Antiarrhythmics

A

Sodium channel blockers

ABSOLUTELY CONTRAINDICATED IN PATIENTS WITH HEART FAILURE OR WHO HAVE JUST EXPERIENCED AN ACUTE MYOCARDIAL INFARCTION

Drugs: Flecainide, propafenone (rythmol)

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13
Q

Flecainide

A

Blackbox warning: preemptive negative chronotropic therapy with digoxin or beta blocker they lower the risk of AV conduction problem; pro arrhythmic effect; cast trial showed increased harm

Contraindication: second or third degree heart block, cardiogenic shock, coronary artery disease such as heart failure or myocardial infarction and concurrent use of ritonavir or amprenavir

Side effects: dizziness, visual disturbances, headache, dyspnea, proarrhythmic

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14
Q

Propafenone (Rythmol)

A

Blackbox warning: cast trial showed inc harm

Contraindication: second or third degree heart block unless patient has pacemaker, sinus bradycardia, cardiogenic shock, hypertension, coronary artery disease such as heart failure or myocardial infarction, bronchospasm disorder or use of Ritonavir

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15
Q

Class II antiarrhythmic agents

A

Block beta receptors and indirectly block calcium channels and the SA and AV nodes

Results and decreased automaticity and conduction velocity in the nodes

these drugs are used to slow the ventricular rate in a supraventricular tachyarrhythmia

Drugs: esmolol (brevibloc) and propranolol (inderal)

Contraindications: second or third degree heart block, sinus bradycardia, sick sinus syndrome, cardiogenic shock, decompensated heart failure, severe hyperactive airway disease especially with propranolol

16
Q

Class III antiarrhythmic agents

A

Block mainly potassium channels resulting in a significant increase in refractory.

Amiodarone and dronedarone also block Alpha and beta-adrenergic receptors and calcium and sodium channels

17
Q

Amiodarone (Cordarone, Pacerone, Nexterone)

A

Blackbox warning p: life-threatening arrhythmia due to toxicity, pulmonary toxicity, liver toxicity, pro arrhythmic

Contraindication: severe sinus node dysfunction, second or third degree heart block, bradycardia causing syncope, cardiogenic shock, hypersensitivity to iodine

Side effects: hypotension, G.I. upset, hypothyroidism/hyperthyroidism, dizziness, bradycardia, peripheral neuropathy/paresthesias, ataxia, trimmer, corneal micro deposits, optic neuritis, pulmonary fibrosis, photosensitivity, increased LFTs, slate blue skin discoloration

Monitoring: pulmonary, thyroid, liver function, ECG, BP, HR, electrolytes, ophthalmic exams, hypertension/bradycardia

Notes: pregnancy category D, infusions longer than two hours must be administered in a non-PVC container with a filter and D5W; premixed IV bags have advantages for this reason; HALF-LIFE IS 40 TO 60 DAYS AND IS THE BEST DRUG FOR PATIENTS WITH HEART FAILURE

18
Q

Dronedarone (Multaq)

Amiodarone’s brother (not a very good drug)

A

Must be administered with meals

Blackbox warning: heart failure and patients with permanent a fib

Contraindications: second or third degree heart block, symptomatic heart failure, heart rate less than 50, con commitment use was strong 3A4 inhibitors, consummate and use of drugs at prolonged QT interval, QTC greater than 500 ms, PR interval greater than 280 ms come along or liver toxicity related to previous amiodarone use, severe hepatic impairment, pregnancy, breast-feeding

Warning: hepatic failure, lung toxicity

Side effects: QT prolongation, bradycardia, increased serum creatinine, diarrhea, nausea, hypokalemia, hypomagnesemia

Monitoring: LFTs especially in the first six months, ECG, potassium, magnesium, creatinine, B UN, heart rate

Notes: pregnancy category X, only used impatient too can be converted to normal sinus rhythm

19
Q

Sotalol (betapace, sorine)

A

Creatinine clearance less than 60 ml/minute decrease frequency

Blackbox warning: initiation and dosage increase should be done in hospital with continuous monitoring, I just dosing interval based on creatinine clearance to decrease risk of proarrhythmia as QT prolongation is directly related to settle all concentration, sotalol injection 10 calls life-threatening ventricular tachycardia and QT prolongation

Contraindication: all beta blocker contraindications

On a Churing: ECG, potassium, magnesium, heart rate, blood pressure, RENAL FUNCTION

20
Q

Dofetilide (Tikosyn)

A

VERY STRICT REMS PROGRAM (must be started and monitored in the hospital initially)

Blackbox warning: must be initiated in a setting with continuous ECG monitoring for a minimum of three days or 12 hours after cardioversion

Contraindications: concurrent use of HCTZ, itraconazole, ketoconazole, megesterol, trimethoprim, verapamil, HR < 50, CrCl < 20, QTc >400msec, hypokalemia, hypomagnesemia

Side effects: headache, dizziness, v. Tachycardia, qt prolongation

Monitoring: ECG, renal function, K, Mg, BP, for first few days. Then monitor QTc and renal function q3months

21
Q

Amiodarone drug interactions

A

When starting decrease dose of digoxin and warfarin by 50%

Also use lower doses of simvastatin, lovastatin, and atorvastatin

22
Q

Dofetilide drug interactions

A

Avoid use with azole antifungals, HCTZ, itraconazole, ketoconazole, megesterol, trimethoprim and others

23
Q

Class IV antiarrhythmics

A

Block L type calcium channels, slowing SA and AV nodal conduction velocity

Drugs: diltiazem and verapamil

Contra: 2nd/3rd degree heart block, sick sinus syndrome, severe hypotension (<90), cardio genie shock, acute MI, pulmonary congestion

Side effects: Edema, headache, av block, bradycardia/hypotension, arrhythmias, HF, CONSTIPATION (more with verapamil), gingival hyperplasia

24
Q

Drugs not included in Vaughan Williams classification

A
  1. Adenosine: slows conduction through AV node
  2. Digoxin: AV node suppression, inc refractory period, and dec conduction velocity. Enhances vegal tone resulting in dec. vent rate in atrial tachy
25
Q

Digoxin (Lanoxin)

A

Therapeutic range for A Fib: 0.8-2ng/ml

Antidote: DigiFab

Contraindications: 2nd/3rd degree heart block, WPW with AFib

Side effects: dizziness, headache, diarrhea, nausea/vomiting/anorexia, mental changes

Toxicity: first signs are nausea/vomiting, loss of appetite and bradycardia other signs include blurred vision, altered color perception, greenish yellow halos around like to objects, abdominal pain, confusion, delirium, arrhythmia

26
Q

Digoxin drug interactions

A
  1. Caution with beta blockers and other drugs that slow heart rate
  2. Decreased renal function requires a decreased dose
  3. Digoxin levels increase with amiodarone, dronedarone, quinidine, verapamil, erythromycin, clarithromycin, itraconazole, cyclosporine, propafenone

HYPOKALEMIA, HYPOMAGNESEMIA AND HYPERCALCEMIA MAY INCREASE THE RISK OF DIGOXIN TOXICITY

27
Q

Amiodarone patient counseling

ASK PATIENT TO READ MEDICATION GUIDE

A
  1. Helps to restore the normal heart rhythm
  2. Take the medication the same time and way every day
  3. Severe lung and liver problems have and frequently occurred tell your doctor immediately if you experience cough, fever, chills, chest pain, dyspnea, coughing up blood, severe stomach pain, yellowing of the eyes or dark urine
  4. Can worsen arrhythmias
  5. Can cause eye problems so have an annual eye exam
  6. May develop pins and needles or numbness and your legs, hands and feet or muscle weakness
  7. Signs and symptoms of thyroid dysfunction
  8. Photosensitivity and blue gray color skin possible

NAPLEX (37 decks)

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