Cardiac drugs Flashcards
functions of cardiac drugs
improve CO, maintain BP and tissue perfusion, minimize workload of the heart, decrease clinical signs, provide best quality of life
introphy
cardiac contraction force
positive inotropes function
increase contractile force
cardiac glycosides
positive inotropes
derived from natural sources
decrease heart rate
antiarrhythmic
decreases dyspnea
low margin of safety
antiarrhythmic
restores normal heart rhythm
cardiac glycoside examples
Digoxin: elixir, injectable, tablet and capsule
Digitoxin: tablet
not vet approved
catecholamines
positive inotropes
hormones produced/released from adrenal cortex
sympathomimetic
used for emergencies only
catecholamine examples
epinephrine/norepinephrine: alpha and beta receptor activity, increase glucose levels, bronchodilation, ER anaphylaxis and cardiac arrest
dopamine: precursor to norepinphrine, used for stimulating heart in acute heart failure or severe shock
dobutamine: administer as CRI, increase CO
isoproterenol: bronchial dilation, not used in vet
vasoconstrictors
increased BP by constricting the blood vessels
vasopressin (vasostrict)
vasoconstrictor drug (aka antidiuretic)
ER to treat shock (shock= decreased BP)
increases fluid retention
also treats diabetes insipidus
what are common adverse effects of cardiac drugs?
anorexia, cardiac arrhythmias, vomiting, diarrhea
vasodilators
decreased BP by dilating the blood vessels
decreases BP, arterial pressure
increases SV, CO
allows heart to eject blood easily
what does long term vasoconstriction do to the body?
causes hypertension and excessive work for the heart and decreases blood flow to the kidneys which can cause renal failure
what types of drugs fall under vasodilators?
ACE inhibitors, Angiotensin receptor blocker (ARB), arteriole dilators, venodilators
angiotensin-converting enzyme inhibitors (ACE inhibitors)
vasodilators
controls CHF
improves tissue blood flow
decreases retention
ACE inhibitor examples
Enalapril (Enacard): FDA approved for dogs
Benazepril: not approved in US
Captopril and Lisinopril: less commonly used
*all ACE inhibitors end in -pril
angiotensin receptor blockers (ARB)
vasodilators
Telmisartan (Semintra): approved in cats, fewer adverse effects than ACE inhibitors
can be harmful to human fetuses
arteriole dilators
vasodilators
Hydralazine: extra-label in vet, reduce overload and increase CO
venodilators
vasodilators
Nitroglycerin ointment: human approved, improves CO and used in right-sided failure
Nitroprusside: works mostly on veins, used for acute failure
inodilator
combined inotrope and vasodilator
helps heart pump more effectively
Benzimidazole-Pyridazinones
which Benzimidazole-Pyridazinone is used as an inodilator?
Pimobendan (Vetmedin)
FDA approved for dogs
used for CHF
often used with other drugs like ACE inhibitors or diuretics
used extra-label in cats
diuretics (heart)
used with other drugs in CHF patients
counteracts retention of fluids
decrease plasma volume
used to alleviate exercise induced pulmonary hemorrhage in horses
spironolactone (Aldactone)
diuretic
potassium sparing diuretic
oral
can be used with Furosemide
furosemide
diuretic
most commonly used for CHF
loop diuretic
oral or IV
beta-adrenergic antagonists “beta blockers”
antiarrhythmics to decrease HR and BP
also used as antihypertensive drugs
ex: Propranolol, Atenolol, Metorolol, Esmolol, Carvedilol
calcium channel blockers
inhibit calcium movement: vasodilation and decrease cardiac muscle activity
Amlodipine
more vasodilation effects than cardiac effects
often used in cats
Diltiazem
used to treat tachycardia and hypertrophic cardiomyopathy in cats
antiarrhythmics
return heart to a more efficient HR and rhythm
divided into categories according to the types of arrhythmia they treat and the actions they have on the cells of the heart
effects: decrease automatic firing of SA node, alter rate of electrical impulse conduction, alter the duration of the refractory period of heart muscle between contractions
how do cardiac arrhythmias effect a patient?
they disrupt coordination of cardiac muscle contractions which decreases the efficiency of cardiac contractions and CO
Lidocaine
antiarrhythmic
used IV to control PVCs (premature ventricular contractions aka extra heartbeats disrupting normal rhythm) and treat ventricular tachycardia
monitor dosing closely since dogs and cats are sensitive to lidocaine toxicity
drugs that effect blood
categorized by effects and goals for use:
1. stop clots from forming
2. stop/control bleeding
3. enhance blood functions
anticoagulants
inhibit clot formation by inactivating 1 or more clotting factors
inhibit clotting in catheters
prevent blood samples from clotting and preserve blood transfusions
treat emboli
heparin
anticoagulant
prevents conversion of prothrombin to thrombin
treats thromboembolism and disseminated intravascular coagulation (DIC)
used in blood tubes and transfusion products (green top)
overdose treated with protamine sulfate
clopidogrel bisulfate
anticoagulant
oral
platelet aggregation inhibitor
used in cats with CHF and HCM
EDTA
anticoagulant
binds to calcium
treats lead poisoning
coumarin derivatives
binds vitamin K
used for long term thromboembolism treatment
contained in rodenticide products
aspirin
anticoagulant
antiplatelet activity (inhibits stickiness)
prevents thromboembolism
blood transfusion anticoagulants
Acid citrate dextrose (ACD)
Citrate phosphate dextrose adenine (CPDA-1)
works by chelating calcium
chelate= create a ring-like complex
hemostatic drugs
promote blood clotting
parenteral or topical
Vitamin K
parenteral hemostatic
Phytonadione
synthetic hemostatic
involved in clotting cascade
treatment of rodenticide activity and bleeding disorders
Protamine sulfate
parenteral hemostatic
basic protein
treats heparin overdose
treats bracken fern poisoning in cattle
slow IV
topical hemostatics
controls capillary bleeding
ex: silver nitrate sticks, ferrous sulfate powder, gelfoam gelatin sponge, thrombogen topical thrombin solution
blood enhancing drugs
affect red blood cells
ex: iron, erythropoietin, darbepoetin, cyanocobalamin, folic acid
