cardio drugs Flashcards
name the two types of heart failure
dilatative/congestive and hypertrophic cardiomyopathy
groups of antiarrythmic drugs
- Na channel blockers
- beta receptor blockers
- potassium channel blockers
- calcium channel blockers
- others - digoxin, atropine
I class antiarrythmic drugs
Na channel blockers
I A class antiarrhythmic drugs
- quinidine
- procainamide
IB class antiarrhythmic drugs
lidocaine, mexiletine,
II class antiarrhythmic drugs
beta blockers - 1st and 2nd generation
1st generation beta blockers
propanolol
1st gen beta blockers act on which receptors
beta1 and 2
2nd gen beta blockers
metoprolol, atenolol, esmolol
2nd gen beta blockers act on which receptors
beta1
3rd generation beta blockers
carvedilol
3rd gen beta blockers act on which receptors
beta1 and peripheral+ alpha1
III class antiarrhythmic drugs what are they
K channel blockers
III class antiarrhythmic drugs
sotalol, amiodarone
IV class antiarrhythmic drugs what are they
Ca channel blockers
two types of Ca channel blocker drugs
- dihydropyridine type - vessels
- non dihydropyridine type - heart
dihydropyridine type Ca channel blockers
amlodipine, nifedipine
non dihydropyridine type Ca channel blockers
verapamil, diltiazem
cause for acute congestive heart failure
sudden deterioration of heart pump function
cause for chronic congestive heart failure
gradual and slow deterioration in heart pump and function and performance
name three main factors affecting heart performance
contractility, preload and afterload
treatment options of chronic heart failure
- incr frequency
- incr contractility
- decr preload and afterload
- inodilators
- vasoactive substances
- diuretics
how do we incr frequency in case of chronic heart failure
only in life threatening cases! - epinephrine -> pos inotropic and chronotropic -> increases myocardial oxygen demand
what substance could be used to increase contractility
digitalis glycosides
decr preoload and afterload what substances could we use
ACE inhibitors
inodilators what substances could be used
PDE inhibitors - Pimobendan, not only incr contractility but dilation too
what vasoactive substances could we use
nitroglycerine
why can diuretics be useful
they can decr preload
cardiotonics for use in acute heart failure
epinephrine, dobutamine, dopamine
cardiotonics for use in chronic heart failure
digitalis glycosides, pimobendan
cardiotonics what do they do to cardiac action
pos inotropic -> cardiac output incr
improves RBF -> water and NA excretion
how do cardiotonics incr vagal tone
neg chronotropic, neg dromotropic
digoxin administration
orally
digoxin is a what
digitalis glycoside, cardiotonic
digoxin protein binding
high when combo with NSAIDs - other drug level v high
where does digoxin accumulate in the body
myocytes
how long should we wait after digoxin admin before measuring plasma level
3-5 days
how is digoxin excreted
kidneys
TI digoxin
small - hypokalaemia - before applying pls check K levels
what does hypokalaemia do to digoxin toxicosis
it promotes it
what will hypercalcaemia do to digoxin toxicosis
promote it
digoxin cardiac side effects
arrhythmias, bradycardia, hypokalamia
digoxin extracardial side effects
GI signs, severe vomiting
digoxin usage
prolong survival time in heart failure, supraventricular tachyarrhythmias
digoxin contraindication
outflow obstruction eg HCM, stenosis
which methylxanthine is also used as an PDE inhibitor
theophylline
what does pimobendan do to preload and afterload
increases them
pimobendan mechanisms of action
PDE inhibtion -cAMP accumulated in myocytes->Ca conc incr-> pos inotropic
Ca sensitiser
arterial and venous vasodilation
when is pimobendan contraindicated
outflow obstruction eg HCM, stenosis
pimobendan administration route
per os
should pimobendan be given before or after feeding
1hr before, F higher on empty stomach
ACE inhibitiors
captopril, enalapril, ramipril, benazepril, lisinopril
ACE inhibitors mechanism of action
blocks renin-angiotnesin system
why can you get a dry cough as a side effect of ACE inhibitors
bc ACE inhibits bradykinin, so when we block it theres more bradykinin
ACE inhibitors pharmacological effects
- arterial vasodilation -> peripheral resistance + afterload decr
- venodilation -> CVP + preload decr
- does not alter contractility -> heart performance incr + blood pressure decr
indications for ACE inhibitors
- heart failure
- hypertension
- proteinuria
in which species is heart failure most common
dogs, horses
in which species is hypertension most common
cats but also sometimes dogs
how do ACE inhibitors help with proteinuria
they vasodilate the efferent vessel-> allows more protein to flow through kidney rather than be filtered into urine
another side effect that can happen with use of ACE inhibitors to help with proteinuria
azotemia - due to incr amount of proteins(N compounds) in blood
ACE inhibitors absorption
good when given orally except captopril
metabolism of enalapril
enalaprilat
metabolite of benazepril
benazeprilat
metabolite of ramipril
ramiprilat
onset of action ACE inhibitors
4-6hrs
duration of action ramipril, enalapril
12-14hrs
duration of action benasepril and lisinopril
12-24 hours
whats special about the metabolism of lisinopril
it has no activation in the liver
excretion of ACE inhibitors
kidney except benazepril - via kidney or via bile
side effects of ACE inhibitors
- azotemia
- hypotension - tiredness, faintness
- anorexia, vomiting, diarrhoea
benazepril dose
0.25-0.5mg/kg SID
which ACE inhibitor is best to use in case of kidney insufficiency
benazepril - can be metabolised via bile too
advantages of using angiotensin II receptor antagonists
more effective, no bradykinin activation
angiotensin II receptor antagonists
losartan, valsartan, telmisartan
why dont we use beta blockers in case of heart failure in animals
they affect renin
ACE inhibitors are often combined with which drugs
spironolactone and furosemide
how does the action of spironolactone help in heart failure
it prevents heart remodelling - its an aldosterone receptor agonist
