Cardiovascular Pharmacology Flashcards
what is stage A of congestive heart failure?
patients at risk: breed predisposition
no clinical signs
what is stage B of congestive heart failure?
pre-clinical, asymptomatic heart disease
what is stage C of congestive heart failure?
patients with past or current clinical signs of heart failure associated with structural heart disease
what is stage D of congestive heart failure?
end-stage heart failure
what dose should you not exceed in acute therapy with furosemide?
8 mg/kg over 4 hr
what is the immediate effect of furosemide related to?
prostaglandin-dependent venodilation
what can ACE inhibitors do with furosemide?
may enhance effects of furosemide and necessitate a decrease in dose of furosemide
what can you use in acute IV therapy for increasing inotropy?
dobutamine or dopamine
how is pimobendan an inodilator?
calcium sensitizer
phosphodiesterase III inhibitor
what are some ACE inhibitors?
enalapril
benazepril
lisinopril
do ACE inhibitors have a preventative effect prior to actual CHF?
no
do ACE inhibitors increase lifespan in CHF?
yes: 50%
why are ACE inhibitors not for acute therapy?
delayed time to maximum effect: 7-10 days
what does digoxin do?
inhibits Na/K ATPase pump on cardiac myocytes
increases vagal tone
what does quinidine do?
blocks open Na channels and has a slow off rate
alpha 1 blocker, vagolytic effect, increases end refractory potential
what is phase 0 of the cardiac action potential in a myocyte and nodal tissue?
myocyte: rapid Na influx
nodal: calcium influx
what increases in heart disease that leads to decreased cardiac output?
total peripheral resistance (afterload)
sympathetic and other hormonal input
preload
what is stage B1 of heart disease?
no radiographic or echocardiographic signs
what is stage B2 of heart disease?
pre-clinical: changes are balanced by compensatory mechanisms
what is recommended for cats with HCM in stage B2?
no clear recommendations
what should you do for dogs with myxomatous mitral valve disease and dilated cardiomyopathy in stage B2?
start pimobendan
mild sodium restriction in diet
what is the immediate effect of furosemide from?
prostaglandin-dependent venodilation
diuretic effect 20-30 minutes later
why might torsemide be slightly advantageous to furosemide with chronic therapy?
may also inhibit aldosterone
how can NSAIDs interact with furosemide?
might block some of its diuretic effects
who can you use spironolactone in?
dogs only
is pimobendan part of standard therapy for familial hypeertrophic cardiomyopathy (FHCM)?
not unless severe CHF
is there synergism with ACE inhibitors and pimobendan for myxomatous mitral valve disease?
not with lifespan
in which cats may pimobendan have a positive effect?
cats with overt heart failure
what can be used for acute vasodilation?
nitroglycerin
sodium nitroprusside
what can be used for chronic vasodilation (decrease afterload)?
pimobendan
ACE inhibitors
amlodipine
prazosin
hydralazine
do ACE inhibitors have an additive effect with pimobendan with CHF from MMVD and DCM?
no
what are the pharmacokinetics of ACE inhibitors?
the drugs are pro-drugs
enalaprilat cleared by renal
benazeprilat cleared by hepatic
why are ACE inhibitors not for acute therapy?
delayed time to maximum effect
what are the adverse effects of ACE inhibitors?
hypotension
exacerbate renal insufficiency
decreased aldosterone
rare idiosyncratic reactions
what are the contraindications for ACE inhibitors?
severe hypotension
sinus node dysfunction
concurrent pulmonary congestion or edema
acute myocardial infarction
hypersensitivity
what does digoxin increasing the vagal tone do?
helps to correct sympathetic:parasympathetic imbalance in heart
decreases rate of SA node and decreases AV conduction
when is a loading dose of digoxin used?
when rapid onset is needed
what are the potential adverse effects of quinidine?
anaphylactoid reaction in horse
hypotension
paradoxical ventricular tachycardia in horse
what is quinidine?
class Ia antiarrhythmic
what is the drug of choice for oral increasing inotropy?
pimobendan
when should you delay initiation of ACE inhibitors?
pre-renal azotemia
dehydration
hypothermia
hypotension
what does digoxin do?
inhibits Na/K ATPase pump on cardiac myocytes
