womp womp

decrease INR

• rifampin

• carbamazepine

• cholestyramine

• colestipol

• sulcralfate

• increased vitamin K intake

• St. John’s Wort

Increase INR

• amiodarone

• erythromycin

• thyroxine

• decreased vitamin K intake

• acute alcohol ingestion

• azole antifungals

• statins

• garlic, gingko biloba

• cranberry juice

• grapefruit juice

Amiodarone

• can be initated OUTPT

• effects of all classes

• variable bioavailability

• delayed onset and long half life

• many AEs

• CI: iodine allergy, sinus node dysfunction, sinus bradycardia, heart block, cardiogenic shock

Dofetilide

• Class 3

• used for maintain normal sinus rhythm in highly symptomatic AF

• 500 mcg PO BID, renal dosing (250 if 40-60, 125 if 20-40)

• CI: QT syndrone, baseline QTx >440, concurrent use w verapamil, cimetidine, HCTZ, trimethorprim, azoles, prochlorperazine, megestrol

• AE: headache, dizziness, syncope, insomia, QT prolongation, torsades

• hold previous AAD at least 3 half lives before initation

• INPT initiation

• Monitor Mg K SCr

Dronedarone

• MOA: class 3

• box warning: increased risk of death, stroke, HF (do not use in HF class 3/4)

• hepatotox

• AE: abdominal pain, bradycardia, NVD, QT prolongation, Torsades

• used for paroxysmal, persistent AFib or AFLu

• amiodarone analogue w shorter half life

Ibutilide

• MOA: Class 3

• IV, cardioversion only (not for chronic management)

• need ECG monitor for at least 4H after admin

• AE: non-sustained VT, QT prolongation, torsades

Sotalol

• MOA: class 2,3

• loading and maintenance dosing

• admitted for at least 3 days

• AE: av block, bradycardia, bronchospasm, HF exacerbations, fatigue, QT prolongation, torsades

Flecainide

• Class 1c

• Cardioversion and maintenance

• AE: AFlu, AV block, dizzuness, dyspnea, HF exacerbation, headache, qt prolongation, vt, visual disturbances

• NOT FOR STRUCTURAL HEART DISEASE

• continuous monitoring initiatially

Propafenone

• class 1c

• cardioversion and maintenance dosing

• AE: aflu, bradycardia, dizziness, dyspnea, HF exacerbation, taste disturbances, VT, visual disturbances

• continuous monitoring w initiation

Drugs that prolong QT

• class 1a, Class 3

• quinolone, macrolide antibiotic

• azole antifungals

• antidepressants (TCAs, SSRI, SNRI, mirtazapine, trazodone)

• Antiemetics (5-Ht3 receptor antagonist, droperidol, phenothiazine)

• antipsychotics (aripiprazole, chlorpromazine, clozapine, haloperiodl, olanzapine, paliperidone, quetiapine, risperidone, ziprasidone)

• donepezil, methadone

Anticoag during cardioversion

• 3 weeks before

• 4 weeks after

• heparin or Lmwh

rhythm control drugs

• dofetilide

• dronedarone

• flecainide

• propafenone

• sotalol

cardioversion drugs

• ibutilide

• amiodarone

• flecainide, propafenone

• IV procainamide (alt)

agents used for sinus rhythm maintenance

• dofetilide, amiodarone

• flecainide, propafenone

• dronedarone

• sotalol (alt)

apixaban

• 5 mg po bid

• if 80+, 60 kg or less, or SCr 1.5+ → 2.5 mg po bid

dabigatran

• 150 mg PO BID

• renal : 75 mg po bid (crcl 15-30)

• ae: GI

• CI: mechanical heart valves

• tartaric acid may cause dyspepsia

edoxaban

• 60 mg po daily

• crcl 15-50: 30 mg

• do not use if crcl under 15 or over 95

PVC

• if symptomatic treat w BB

Non-sustained VT

• if EF over 40 and no symptoms, no tx

• if symptoms, BB (alt sotalol, amiodarone)

Sustained VT

• if LV preserved: procainamide (alt amiodarone, lidocaine)
  if LV dysfunction: BB, ICD

Procainamide

• renal adjustment, major metabolite w K channel blocking effect

• AE: hypotension, positive ANA

• CI: allergy to ESTER TYPE LOCAL ANESTHETIC, heart block, av blokc, lupus, torsades

• treat sustained vt with preserved LV

Sotalol

• alt to treat

• beta blocking effect from R-isomer

• renally adjusted

• CI: asthma, bradycardia, heart block, QT syndrone, HEART FAILURE

Lidocaine

• caution in hepatic impairment

• AE: CNS tox

• CI: allergy to AMIDE type anesthetic, Wolff-Parkinson,White syndrone, severe heart block

• treat vfib, vtach

Epinephrine

• alpha/beta agonist → vasoconstrictor, increase rate/force of heart contraction

• indication: VF, PVT, asystole, PEA

Torsades de pointes treatment

• magnesium sulfate 1-2g

• remove qt prolonging drugs

• target K > 4, Mg >2

class 1a

prolong action potential, increase QRS

class 1b

shorten action potential, rapid dissociation, increase QRS

class 1c

no effect on action potential, slow dissociation, increase QRS

class 3

prolong action potential

class 4

slow conduction, decrease HR, increase PR

class 2

decrease HR, increase PR

warfarin pearls

• doses above 10 mg → increased risk of anticoag, skin necrosis

• S warfarin more potent, metabolized by 2C9, shorter half life