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Pharmacology > Cardiovascular System Drugs (Ex2) > Flashcards

Cardiovascular System Drugs (Ex2) Flashcards

1
Q

What are 4 cardiac stimulants?

A

Beta 1 agonists
Phosphodiesterase inhibitors
Glucagon
Calcium salts

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2
Q

What kind of drugs are Digitalis Glycosides?

Name 3 of them

A
  • positive inotropic drugs
  • Digitoxin
  • Digoxin
  • Ouabain
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3
Q

Digoxin

classification, MOA

A
  • digitalis glycoside (pos inotropic)
  • inhibits Na-K ATPase in myocardial cell membrane, increasing Na available for exchange with Ca
  • results in increase in intracellular Ca leading to positive inotropic effect
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4
Q

Digoxin

cardiovascular effects

A
  • positive inotropic effect
  • reduction in sinus rate and slowing AV conduction
  • prolonged PR intervals in ECG
  • increased mechanical efficiency of failing heart
  • normalization of blood pressure and peripheral resistance
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5
Q

Digoxin

effects on kidney and GI tract

A

Kidney
- diuretic effect secondary to increased cardiac output
GI
- irritation, vomiting, anorexia

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6
Q

Digoxin Pharmacokinetics

A
  • administered orally, can be given slow IV in emergencies
  • oral bioavailability better as elixir than tablet
  • small amount metabolized in liver
  • undergoes hepatic recycling
  • excretion renal in dogs and horses, renal and hepatic in cats
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7
Q

Digoxin therapeutic uses and adverse affects

A
  • congestive heart failure
  • atrial arrhythmias in dogs
    Adverse: narrow safety margin
  • cats more sensitive than dogs
  • tachy and bradyarrhythmias
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8
Q

Predisposing factors for tachyarrhythmias cause by Digoxin

A
  • hypokalemia, hypomagnesemia
  • hypercalcemia, hypernatremia
  • hypo/hyperthyroidism
  • hypoxemia
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9
Q

Treatment of tachyarrhythmia and bradyarrhythmia caused by Digoxin

A 
T: drug withdrawal
- potassium IV
- antiarrhythmic drugs
- cholestyramine
- digoxin immune Fab (antibody)
B: drug withdrawal
- Atropine
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10
Q

What type of drugs are Beta 1 Agonists?
When are they used?
Name 2 drugs

A
  • positive inotropic drugs
  • less likely to cause tachyarrhythmias
  • only used in emergencies (one dose/shot)
  • Dopamine and Dobutamine
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11
Q

Pimobendan

classification, uses

A
  • inodilator (pos inotrope and vasodilator)
  • treat CHF in dogs
  • as adjunctive therapy in improving quality of life in dogs with heart failure due to dilated cardiomyopathy and degenerative vascular disease
  • can be used with furosemide, spironolactone, or ACE in heart failure patients
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12
Q

Pimobendan MOA

A
  • sensitization of the cardiac contractile apparatus to Ca by enhancing interaction between Ca and troponin C complex
  • has the potential to increase intracellular Ca and increase myocardial oxygen consumption, bc inhibits PDE III and V, causing vasodilation of arteries and veins, resulting in reduced pre- and afterload
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13
Q

Pimobendan

side effects and contraindications

A
  • may cause diarrhea, vomiting, inappetence, seizures, and PU-PD
  • less arrhythmogenic than digitalis
  • should not be used in hypertrophic cardiomyopathy or in clinical conditions where increase of cardiac output is not possible
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14
Q

Pimobendan pharmacokinetics

A
  • absorbed rapidly on oral ingestion
  • bioavailabilty of 60%
  • metabolically activated in liver
  • metabolites excreted in feces
  • bound to plasma proteins
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15
Q

What are 4 vasodilator drugs?

A
  • ACE Inhibitors (block angiotensin II formation)
  • Hydralazine
  • Nitrates
  • Prazosin
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16
Q

Carvedilol

classification, MOA, uses

A
  • nonselective beta blocker and alpha 1 blocker
  • antioxidant
  • inhibits endothelin release
  • used in early trtmt of CHF due to dilated cardiomyopathy to blunt the harmful effects of sympathetic NS on the heart
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17
Q

What are the 3 mechanisms of arrhythmias?

A
  • abnormal automaticity
  • abnormal conductance
  • disturbances in both automaticity and impulse conduction
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18
Q

What are the causes of arrhythmias?

A
  • imbalance of sympathetic and parasympathetic
  • changes in serum K, Ca, or Mg
  • hypoxemia
  • acidosis
  • mechanical trauma
  • myocardial disease
  • cardiac ischemia
  • myocardial infarction
  • drugs
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19
Q

What are the different class of drugs for tachyarrhythias?

A

Class 1: Na channel blockers
- local anesthetics, membrane stabilizers
Class 2: beta blockers
Class 3: prolong action potential duration
- K channel blockers
Class 4: Ca channel blockers

20
Q

Effect of Class 1A, 1B, and 1C drugs (against tachy)

A

1A: prolong action potential
1B: shorten action potential
1C: no effect on action potential

21
Q

Quinidine

class, uses

A
  • class 1A
  • ventricular arrhythmias
  • atrial fibrillation in horses, cattle, and large dogs
22
Q

Procainamide

class, use

A
  • class 1A

- more effective for ventricular arrhythmias than atrial arrhythmias

23
Q

Lidocaine

class, uses

A
  • class 1B
  • the IV drug of choice for ventricular arrhythmias due to general anesthetics, surgery, ischemia, and trauma
  • digitalis-induced arrhythmias
24
Q

Phenytoin

class, use

A
  • class 1B
  • digitalis-induced arrhythmias in dogs only
  • IV administration
25
Q

Propranolol

class, uses

A
  • class 2
  • paroxysmal supra-ventricular tachycardia
  • digitalis-induced tachyarrhythmias
  • arrhythmias due to inhalation anesthesia
26
Q

Bretylium

class, use

A
  • class 3

- refractory and recurrent tachyarrhythmias

27
Q

Verapamil
Diltiazem
(class, uses)

A
  • class 4
  • supra-ventricular tachyarrhythmias
  • myocardial hypertrophy
28
Q

What 3 drugs are used for bradyarrhythmias?

A

Atropine
Isoproterenol
Epinephrine

29
Q

What type of drug is Enalapril?

A

ACE inhibitor

30
Q

Explain the Renin-Angiotensin-Aldosterone System

A
  • angiotensinogen converted to angiotensin 1 by renin
  • angiotensin 1 converted to angiotensin 2 by ACE kininase, which also inactivates bradykinin
  • angiotensin 2 stimulates vasoconstriction and secretion of aldosterone by the adrenal cortex
31
Q

MOA of ACE inhibitors

A
  • inhibit angiotensin-converting enzyme (ACE kininase)
  • inhibit angiotensin 2 synthesis
  • inhibit aldosterone (diuretic, increase serum K)
  • reflex increase in renin
  • increased bradykinin level (vasodilation)
32
Q

Therapeutic uses of ACE inhibitors

A
  • CHF
  • hypertension
  • chronic renal insufficiency in cats
33
Q

Pharmoacokinetics of ACE inhibitors

Enalapril, Captopril, Benazepril, Lisinopril

A
  • Enalapril is available orally and parenterally, others only oral
  • Enalapril has slower onset and longer duration than Captopril in the dog
  • Food reduces intestinal absorption of Captopril
  • Enalapril and Benazepril are activated in the liver
  • Benazepril is least likely to require doasge modification in renal failure patients, bc 50% is excreted in bile
  • Benazepril and Lisinopril are long-acting (administered once daily)
34
Q

Adverse Effects of ACE inhibitors

A
  • hypotension
  • may lower intraglomerular pressure, decreasing GFR in animals with hypertension and azotemia
  • Captopril may cause idiosyncratic glomerular disease in dogs, has more GI side effects, and may cause neutropenia, proteinuria, and skin rash in humans
35
Q

Losartan

classification, MOA, use

A
  • angiotensin 2 antagonist
  • competitive antagonist of angiotensin 2 receptors
  • antihypertensive
36
Q

Hydralazine

classification, MOA

A
  • direct acting arteriolar vasodilator
  • increase local concentrations of PGI2
  • inhibit Ca influx into smooth muscles of arteries
37
Q

Nitrates
(classification, MOA)
Name 3

A
  • direct acting vasodilator
  • sodium nitroprusside, nitroglycerin, isosorbide dinitrate
  • formation of NO which activates guanylyl cyclase
  • increase cyclic GMP
  • stimulation of GMP-dependent protein kinase
  • alteration of phosphorylation of proteins in smooth muscle, and dephosphorylation of myosin light chain
  • relaxation of smooth muscle of blood vessels
38
Q

What are 3 classifications of calcium channel blockers?

- What drugs are in each?

A
  • diphenyl alkylamines (verapamil)
  • benzodiazepines (diltiazem)
  • dihydropyridines (amlodipine, nifedipine)
39
Q

Calcium channel blockers MOA

A
  • competitive antagonism on Ca channels
  • inhibit influx of extracellular Ca across myocardial and smooth muscle cell membranes
  • decrease in intracellular Ca inhibits myocardial contraction and results in dilation of coronary and systemic arteries
40
Q

Effects of Ca channel blockers on the heart

A
  • negative inotropic and chronotropic effect
  • increase oxygen delivery to myocardial tissue
  • decrease afterload
  • coronary vasodilation
41
Q

Effects of Ca channel blockers on the blood vessels

A
  • vasodilation of arteries and veins
  • decrease peripheral resistance
  • decrease systemic blood pressure
42
Q

Therapeutic uses of Ca channel blockers

A
  • antiarrhythmic (verapamil, diltazem)
  • antihypertensive (amlopidine, unless cause is hyperthyroidism, then use beta blocker
  • myocardial hypertrophy (diltazem)
  • antianginal: ischemic heart disease (neg inotropic and coronary vasodilation)
43
Q

Adverse effects of Ca channel blockers

A
  • bradycardia and AV block (treat with atropine)
  • hypotension
  • GI side effects
  • elevated liver enzymes
44
Q

Which types of drugs are used as antihypertensive drugs?

A
  • diuretics
  • beta blockers
  • vasodilators
  • Ca channel blockers
45
Q

Which drugs are used to treat emergency hypertension?

include mode of administration

A
  • hydralazine or sodium nitroprusside IV
  • propranolol or acepromazine IV
  • phentolamine IV
  • oral calcium channel blockers, prazosin, or ACE inhibitors
46
Q

What is the drug of choice to treat Pheochromocytoma-induced hypertension?

A

Phenoxybenzamine

Pharmacology (14 decks)

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