Cardiac Drugs

Question 1

MoA of furosemide

Answer 1

Inhibition of the Na/K/Cl co-transporter in the thick ascending loop of henle, resulting in decreased sodium and chloride reabsorption

Question 2

What is furosemide used for in horses?

Answer 2

Exercise Induced Pulmonary Hemorrhage

Question 3

ADEs of furosemide

Answer 3

• Acute administration may lead to dehydration, acute intravascular volume reduction
• May precipitate acute renal failure
• Electrolyte abnormalities (hyponatremia, hypokalemia, hypochloremia, hypocalcemia, hypomagnesemia)

Question 4

What kind of medication is spironolactone? MoA?

Answer 4

Potassium-sparing diuretic
Competitive antagonism of aldosterone

Question 5

What disease can spironolactone be used for in cats?

Answer 5

Primary aldosteronism

Question 6

Clinical use of spironolactone in dogs

Answer 6

• Management of refractory edema
• Adjunct treatment of heart failure

Question 7

Briefly discuss RAAS

Answer 7

• Renin (produced by kidneys) metabolizes angiotensinogen to angiotensin I
• Angiotensin I converted to II by ACE
• Angiotensin II potent vasoconstrictor and stimulates release of aldosterone
• Aldosterone causes Na retention

Question 8

MoA of ACEIs

Answer 8

Inhibit ACE, therefore blocking conversion of angiotensin I to II, preventing vasoconstriction and reduce Na and water retention

Question 9

What two ACEIs are commonly used in veterinary medicine?

Answer 9

Benazepril
Enalapril

Question 10

Clinical use of ACEIs

Answer 10

Treatment of CHF
Systemic hypertension
PLN

Question 11

MoA of amlodipine

Answer 11

Calcium channel blocker

Question 12

What species is amlodipine most commonly used?

Answer 12

Cats

Question 13

MoA of sildenafil

Answer 13

Phosphodiesterase inhibitor (PDE5)

Question 14

Fun fact about sildenafil

Answer 14

Viagra! PDE5 found in lungs and corpus cavernosum

Question 15

What is sildenafil used for?

Answer 15

Pulmonary hypertension

Question 16

What does digoxin do to heart rate and contractility?

Answer 16

Decreases HR and improves contractility

Question 17

Due to digoxin’s narrow therapeutic index, it has been replaced by…

Answer 17

Pimobendan

Question 18

What arrhythmias can digoxin treat?

Answer 18

Supraventricular - atrial fibrillation/flutter

Question 19

MoA of Pimobendan

Answer 19

Calcium sensitizes - positive inotrope
PDE3 inhibition - vasodilator

Question 20

Clinical use of pimobendan

Answer 20

Treatment of CHF secondary to MVD, DCM in dogs

Treatment of CHF with LV systolic dysfunction - DCM, HCM

Question 21

What receptors does epinephrine act on?

Answer 21

Mixed adrenergic agonist
B1, B2, and A1

Question 22

Effects of epinephrine on B1

Answer 22

Positive inotrope
Positive chronotrope

Question 23

Effects of epinephrine on B2

Answer 23

Bronchodilation and increased oxygenation

Question 24

Effects of epinephrine on A1

Answer 24

Vasoconstriction

Question 25

T/F: Effects of dopamine are dose-dependent

Answer 25

True - work on different receptors at different dosages

Question 26

@ 2-5ug/kg/min, 5-10ug/kg/min, >10ug/kg/min what receptors does dopamine act on?

Answer 26

- Dopaminergic: Renal vasodilation - B1: positive inotrope and increased cardiac output - A1: pressor effects

Question 27

What receptors does Dobutamine work on?

Answer 27

DoBBButamine - B1

Question 28

Explain how vasopressin acts on BP

Answer 28

Vasopressin - ADH (antidiuretic hormone) Water retention

Question 29

Five classes of antiarrhythmic drugs

Answer 29

I. Sodium Channel Blockers II. Beta blockers III. Potassium Channel Blockers IV. Calcium Chanel Blockers V. Other “Some Big Puppies Can’t Oxygenate”

Question 30

Name the two main sodium channel blockers used

Answer 30

Quinidine Lidocaine

Question 31

Toxic doses of lidocaine

Answer 31

8mg/kg cows, sheep, goats 4mg/kg dogs 2mg/kg cats and horses

Question 32

ADE of lidocaine

Answer 32

CNS excitation, muscle tremors, ataxia, vomiting

Question 33

What do beta adrenergic antagonists do?

Answer 33

Decrease rate of AV conduction

Question 34

Clinical indications of beta-blockers

Answer 34

Sinus tachycardia Ventricular and supraventricular arrhythmias Chronic hypertension Pheochromocytoma Decreased AH production in glaucoma

Question 35

Is propranolol selective or non-selective? When is this drug contraindicated?

Answer 35

Non-selective Blocks both B1 and 2 Avoid in patients with primary respiratory disease (bronchoconstriction)

Question 36

Why is atenolol preferred over propranolol?

Answer 36

Atenolol is B1-selective and propranolol is non-selective, so you have less bronchospasm

Question 37

ADEs of B blockers

Answer 37

Bradyarrhythmias Hypotension Heart failure - decompensation and worsening of CHF

Question 38

Sotalol and amiodarone are __________________

Answer 38

Potassium channel blockers