Antiarrythmic Drugs Flashcards
Digoxin function in arrhythmia
(Last line) Rate control ONLY on resting HR
(negative ionotropic)
Only for supraventricular arrhythmia
Enhance vagal tone –> decrease ventricular rate
Digoxin
Brand
Digox
Lanoxin
Therapeutic range for Afib (Digoxin)
0.8-2 ng/mL
Signs of Digoxin toxicity
Nausea/vomiting, loss of appetite and bradycardia
Double vision, confusion, arrhythmias
What factors (include electrolytes) increase risk of toxicity (digoxin)
Hypokalemia (<3.5 mEq/L), hypomagnesia, hypercalcemia. Hypothyroidism
Reduce renal function, dehydration
Digoxin renal adjustments?
Oral:IV conversion?
When do you obtain digoxin level?
What is the antidote and when do you give it?
Digoxin
CrCl < 50 reduce dose or reduce frequency
Reduce dose by 20-25% when going from po to IV
Get levels 12 to 24 hours after a dose?
Antidote: DigiFab give when levels are high AND symptoms present.
Drugs that increase digoxin levels?
Amiodarone, dronedarone, quinidine, propafenone, verapamil
Azoles, macrolide
Digoxin and amiodarone or dronedarone what do you do?
Reduce Digoxin by 50%
Digoxin is a substrate of what major enzyme
3A4 and P-BP
Adenosine (use)
Restore normal sinus rhythm
Slow conduction through AV nodes (supraventricular re-entrant tachyarrhythmias)
Class IV (MOA)
Verapamil, Diltiazem.
Block calcium channels (phase 2)
Slow ventricular rate (negative chronotropic )
Non-dihydropyridine CCB contraindication
Severe hypotension ( < 90 mmHg)
Acute MI —> heart failure
2nd/3rd degree heart block
May be used in HF with preserved EF
Non-dihydropyridine CCB side effect
Edema, constipation ( verapamil), gingival hyperplasia, bradycardia (- chronotropic), arrhythmia (- ionotropic), hypotension
Dofetilide (REMS)
BBW
Must be started inpatient with ECG monitoring for at least 3 days
Tikosyn monitoring
ECG, BP, SCr, HR, electrolyte (K, Mg)
Dofetilide
CrCl < 60mL/min reduce dose
Contraindicated: CrCl <50, azoles, antiviral, verapamil
…
Sotalol
Renal adjusted (< 60 mL/ min)
Can’t substitute Betapace with Betapace AFib
Dronedarone BBW
HF (class IV or any class recently hospitalized) Permanent AFib
Dronedarone
Side effect
Pregnancy category
QT prolongation, increase SCr
Category X
Amiodarone BBW
Must be started in hospital
Pulmonary toxicity
Liver toxicity
Proarrhythmic
Amiodarone allergy caution
Contraindicated with iodine allergy
Amiodarone side effect
Hypotension, bradycardia, corneal microdeposits, GI, hypothyroidism/hyperthyroidism (more hypo), blue-gray skin
Infusion of amiodarone
Non-polyvinyl chloride (PVC) container such as glass, or polyolefin if infusion is longer than 2 hours
Amiodarone
Half-life
Pregnancy
40- 60 days
Category D
Which patients is amiodarone drug of choice?
Heart failure
Dronedarone drug interaction
It’s a inhibitor of 2D6 and 3A4
Amiodarone drug interaction
Amiodarone is an inhibitor of 2C9, 2D6, 3A4
Reduce warfarin by 30-50%
Do not exceed 20 mg Zocor, 40mg of mevacor
Class III antiarrhythmic drug interaction
All are proarrhythmic agents (prolong QT)
Do not use grapefruit juice
Avoid ephedra and St. John wort
Class II (beta blocker) MOA
Slow ventricular rate (blocks calcium indirectly) phase 3
Class Ib ( allergy contraindication)
Corn
Quinidine side effect
Diarrhea, stomach cramp, cinchonism (hearing loss)
Hemolysis, drug induce lupus
Procainamide side effect
Metabolized acetylation–> NAPA (metabolite)
Lupus, hypotension
Disopyramide side effect
Anticholingeric (dry eyes, dry mouth, constipation, urinary incontinence)
Class Ic negative iontropic property contraindicated in?
Heart failure and recent MI
Class Ib side effect
CNS cross BBB
Quinidine drug interaction
Inhibit 2D6 and 3A4
Reduce digoxin by 50%
Which rhythm can class IB used for?
Only ventricular arrhythmias
