Cardiac drugs Flashcards
nitroprusside: indication
-HTN, CHF without ischemia
nitroprusside: side effects
hypotension, reflex tachy, cyanide tox, methemoglobinemia
SNP: action
- direct smooth muscle relaxation
- decreases preload and afterload
SNP titration
- up to 10 ug/kg/min
- don’t give over 1 mg/kg in 2.5 hrs
- toxic levels of 100 ug/kl occur if more than 1 mg/kg given over 3 hours
cyanide tox
- unexplained metabolic acidosis
- treat with sodium nitrate and thiosulfate
Nitroglycerine: indication
Myocardial ischemia, pulmonary HTN, systemic HTN
NG: side effects
hypotension, arrhythmia, myocardial ieschemia
NG: action
- direct smooth muscle relaxation
- reduces preload
0. 25-5 ug/kg/min,
epinephrine: indications
hypotension, LV failure, bronchospasm
epi: side effects
HTN, arrhythmias, myocardial ischemia
Dosage effects
- 1-2 ug/min-b2-bronchodilation (0.01-0.05 ug/kg/min)
- 4 ug/min-stim b1 receptors, LV improves
- 10-20 ug/min–both and alpha and beta receptors activated
- renal blood flow decreases, CO and HR increase
Dopamine: indications
-hypotension, oliguria
dopamine: side effects
HTN, tachycardia, arrhythmia, myocardial ischemia
dopamine: effects
-increase contractility, renal blood flow, GFR 1-30 ug/kg/min-dopaminergic 2-10 beta >10-alpha -less arrhythmogenic than epi -modiest inc in HR
dobutamine: indications
-Heart failure
dobutamine: side effects
hyper and hypotension, tachycardia, arrhythmia, myocardial ischemia
dobutamine action
- selective b1 agonist
- dose-dependent increases in CO without marked increases in HR and BP
- acts directly to increase contractility
Amrinone: indication
-short term CHF
amrinone: side effects
thrombocytopenia, tachyphylaxis, hypokalemia, GI effects–marked hypotension in hypovolemic pts
PDEI
- PDE breaks down cAMP
- PDEI–inc cAMP, improves uptake, storage and release of ca from SR during excitation-contraction coupling
-amrinone: action
- inc CI, dec SVR and cardiac filling pressures
- HR usu unchanged to slightly inc
- in pts with CHF, does not significantly inc myocardial O2 consumption
- enhances AV conduction–pts with atrial arrhythmias should be pretreated w/ digitalis
milrinone
- bypyridine derivative
- positive inotropy, vasodilation
- greater decrease in LV pressure and BP compared to amrinone b/c has enhanced vasodilatory properites
chronotropes
atropine, isoproternol
isoproterenol
- b1 and b2 agonist
- 3rd degree HB and EMD
- may decrease SVR and MAP at same time it’s increasing HR, contractility and myocardial O2 consumption
SVT rx
- adenosine–6 mg, then 12mg, then 12mg
- verapamil-can be lethal in VT
amiodarone
- antidysrhythmic
- recurrent or refractory V-tach or V-fib
- inc refractory period, reduce membrane excitability of heart
- use prior to 3rd or 4th counter shock in cardiac arrest
LIdcoaine
- suppresses ventricular arrythmias-PVC, Vtach, Vfib
- decreases automaticity without causing myocardial depression
- can block chronotropy and dec sympathetic NS outflow
LIdo and defibrillation
- disrupts subsequent defib and cardioversion by increasing current and energy requirements, a process worsened by acidosis
- asystole has been associated with prophylactic use of lido for rx of cardiac arrest\
LIdo dosing
- 1.5-6ug/cc is therapeutic level
- 1mg/kg bolus, 15-60 ug/kg/min infusion
- rate of metabolism is dependent on hepatic blood flow and hepatic function
Procainamide
-suppresses ventircular ectopy when lido is ineffective
