Flashcards in Ch.22: Inotropes (Swift) Deck (11):
how do inotropic drugs increase contractility?
increase Ca available to increase interaction of actin/myosin
cost of positive inotropes
-inc. myocardial O2 consumption
4 classes of inotropes
1) cardiac glycosides
2) beta-adrenergic agonists
3) phosphodiesterase inhibitors
4) Ca sensitizing agents
digoxin is what class of inotrope?
MOA of cardiac glycosides*
-inhib. Na/K ATPase pump --> inc. intracellular Na, which exchanges for Ca --> increased contractility
-DELAYS conduction of SA/AV nodes
cardiac glycosides are used in patients with:***
-systolic myocardial (pump) failure (i.e. severe valvular dz, DCM)
digoxin is dosed based on**
LEAN body weight. Be careful when dosing in fat/edema dogs
where is digozin excreted?**
kidneys. be careful when using in D/C with renal disease!!
digoxin therapeutic window
narrow. Overdose results in cardiac toxicity (tachy/bradyarrhythmias), CNS signs (i.e. CTZ stim. --> vomiting), and GI signs (v/d/nausea)