pharm 2 Flashcards
Digoxin
Atria rate control, CHF positive inotrope
Stimulates PNS to increase vagal tone - doesn’t work w/ exercise
Slow onset, loading dose, week till steady state - 0.8-2 ng/mL (0.5-1 w/ CHF)
Digoxin Toxicity
Decreased renal function, electrolyte disturbances
DI w/ amiodarone, verapamil
Sx: AV block, junctional tachycardia, ventricular arrhythmias, visual disturbances (yellow-green, halos), dizziness, weakness, N/V/D, anorexia
Adenosine
Convert PSVT to sinus rhythm
Activates potassium channels to hyperpolarize cell membrane
Very short half-life - 10 seconds
CI: 2/3 degree block, sick sinus syndrome w/o pacemaker
Atropine
Used to tx symptomatic bradycardia
Parasympatholytic = enhance SA and AV automaticity by blocking PNS/ACh
CI: angle-closure glaucoma, obstructive uropathy (BPH), Tachycardia, Bowel obstruction/altered transit (ischemic bowel)
May induce tachycardia
Class I
Sodium channel blockers
Grouped according to how quickly they move on/off sodium channels
Class Ia
Proarrhythmic - emergent only
Use for atrial and ventricle rhythms - increase SA/AV automaticity
A-fib/flutter - need BB/CCB on board to prevent tachycardia
Procainamide IV
Class Ib
Used for ventricular arrhythmias (ACLS)
Work on ischemic/infarcted tissue (acute MI)
Lidocaine IV, Mexiletine PO
Class Ib toxicity
Seizure
Respiratory arrest
Class Ic
Use only when nothing else works - Amiodarone is more effective
Flecainide = rhythm control a-fib/flutter
Propafenone = rhythm control w/ atrial dysrhythmias
CI w/ structure heart disease
Class II
Beta blockers - Metroprolol best w/o kidney SE
Used for ventricular/supraventricular arrhythmias
Slow AV/SA rates/conduction, negative inotrope to decrease O2 consumption
SE: bronchospasm, depression, bradycardia, ED, worsen CHF
Class III
Potassium channel blockers
Antiarrhythmics - prolong action potential
Monitor for EKG changes
CI w/ drugs that prolong QT interval
Amiodarone
Class III - a-fib/flutter, ventricular arrhythmias
Need large dose, goes everywhere, 6 mo 1/2 life
Toxicities w/ deposition into organs - pulmonary is life-threatening
Monitor PFT, CXR, DLCO yearly - take off w/ changes
Monitor TSH, CBC, LFTs q6mo
SE: GI w/ high dose, DI - CYP3A4, increase warfarin and digoxin effects
Sotalol
Class III, BB like properties
Prolongs QT - monitor 3 days after start
Use for V-tach, A-fib/flutter
Renal clearance
Risk for Torsades
Dofetilide
Class III - proarrhythmic
a-fib/flutter
SE: Prolong QT, torsades, HA, dizziness, many DI w/ common Abx - macrolides, Bactrim, CCB
Ibutilide
Class III
IV only, acute a-fib/flutter conversion to sinus
SE: torsades
