Antiarrhythmics Flashcards
what is the resting membrane potential of the heart determined by?
high Na concentration outside the cell, maintained by Na-k ATPase pump
how is quinidine metabolized?
hepatic metabolism
vomiting, tinnitus, HA, blurred vision
cinchonism
which class Ia drug would be good to monitor serum levels of to monitor toxicity and efficacy?
procainamide
SE:significant anticholinergic effects in addition to being a Na channel blocker
disopyramide
which antiarrhytmic is cleared renally (+hepatic)?
disopyramide
lidocaine is effective only in _______arryhtmias
ventricular
how is lidocaine administered?
IV
SE: CNS side effects mostly incl dizziness, paresthesias, confusion, coma, lethargy, tremor, seizures
lidocaine
flecainide and propafenone are used for only ______arrhytmias, recommended specifically for patients with _________
atrial
recommended for patients with lone A fib (nothing else)
how is flecainide metabolized?
hepatically + renally
which 2 class 1 drugs are fairly well tolerated with few side effects?
propafenone and flecainide
what have studies shown about ALL class I drugs in patients with CHF?
INCREASED MORTALITY
which class of antiarrhytmics have been shown to reduce mortality?
ONLY the beta blockers
sotolol is class III drug, as well as a ?
beta blocker (class II)
main issue with sotolol?
profound INCREASE IN QT INTERVAL (high risk of Torsades)
which class III drug? high bioavailability, hydrophilic, MUST doses down in renal failure
sotolol
amiodarone has a low or high Vd?
very high Vd, and LOONNNG half life
cardiac abnormalities assc’d with amiodarone
minimal risk of torsades
is amiodarone safe or unsafe for heart failure patients
safe for CHF
pulmonary abnormalities assc’d with amiodarone
3% get pulmonary fibrosis, delayed hypersensitivity pneumonitis
ways to monitor pulmonary risks?
have patient report unexplained dyspnea, cough and fever
thyroid abnormalities assc’d with amiodarone
can cause hypo or hyperthyroidism
______% of amiodarone is _____
44% of amiodarone is iodine
ocular abnormalities assc’d with amiodarone
- corneal deposits in almost ALL patients
2. halos, photophobia, overt retinopathy
neuro abnormalities assc’d with amiodarone
20-40% patients have tremor, ataxia, peripheral neuropathy
derm abnormalities assc’d with amiodarone
photosensitivity,blue green discoloration in sun exposed areas
hepatic abnormalities assc’d with amiodarone
4-35% have asympatomatic elevations in transaminases & bilirubin
some get hepatitis
GI abnormalities assc’d with amiodarone
N/V common
loss of taste, constipation
amiodarone decreases effectiveness of what drugs (2)?
- digoxin
2. warfarin
amiodarone increases effectiveness of what drugs (3)?
- beta blockers
- phenytoin
- theophylline
what is amiodarone primarily used for?
- SVT (esp AF)
- VT
- VF
contrast dronaderone to amioradone
Iodine–>CH3 = lower Vd, safer
BUT less effective for A fib
cardiac abnormalities for dronaderone
CONTRAINDICATED in patients with health failure
AE: rash, nausea, diarrhea, mild QT prolongation, contraindicated in severe CHF
dronaderone
what is a new agent used for acute conversion of AF to NSR, and for maintenance of NSR?
dofetilide
which drug? HIGHER incidence of torsades than sortolol, HA, chest pain, dizziness. requires 3 day inpatient initiation.
dofetilide
C/I: verpamil, cimetidine, trimethoprim, ketoconazole, prochlorperzine, megasterol
dofetilide
how to tx pt with A fib with no other heart disease?
flecainide or propafenone
how to tx pt with A fib with h/o CAD but normal EF?
sotolol
how to tx pt with A fib with CHF?
amiodarone or dofetilide
