Term
| What are the 6 general classes of drugs used to treat cardiac disease? Give an example of one drug in each class. |
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Definition
1. ACE Inhibitors (enalapril)
2. Diuretics (furosemide)
3. Cardiac Glycosides (digoxin)
4. Calcium sensitizers (pimobendan)
5. Vasodilators (nitroglycerin)
6. Anti-arrhythmics (procainamide, atenolol) |
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Term
| What are the main therapeutic uses of ACE Inhibitors and how are they effected? |
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Definition
| Abate hypertension and reduce cardiac remodeling, via balanced vasodilation (stops ATII's vasoconstriction) and reduced Na+/water retention (indirectly inhibits aldosterone release). |
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Term
| Talk about enalapril. Class of drug? Formulation? Labeled uses? Side effects? |
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Definition
ACE Inhibitor.
IV and oral.
Approved for dogs in US and Europe (CHF)
Side effects: hypotension, decreased renal function (reversible with decreased drug dose) |
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Term
| Talk about benazapril. Class of drug? Formulation? Labeled uses? Side effects? |
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Definition
ACE Inhibitor.
Oral only.
Approved for dogs in some European countries.
Side effects: hypotension, decreased renal function (reversible with decreased drug dose) |
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Term
| What are the 3 classes of diuretics, how do they differ in action, and which are more potent? |
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Definition
1. Loop diuretics (a.k.a. "high-ceiling" diuretics: inhibit Na+ and Cl- reabsorption in LOH (by blocking Na+/K+/Cl- cotransport).
2. Potassium-sparing diuretics: Block Na+/K+ exchange by antagonizing aldosterone (bind competitively to aldosterone receptors in DT, CD).
3. Thiazide diuretics: Inhibit NaCl reabsorption in DT.
Loop (25%) > thiazide (10%) > K+sparing in terms of potency (% natriuresis). |
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Term
| Talk about furosemide. Class of drug? Formulation? Other similar drugs in the class? Serum half-life? Side effects? |
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Definition
Loop diuretic.
IV, SQ, oral.
Furosemide/Lasix most commonly used, but interest in torsamide is increasing. Also bumetanide.
Serum T1/2 only 1-1.5 hrs (peak effect 30 min post-IV dose)
All diuretics can cause azotemia, weakness, dehydration (duh), hypotension, electrolyte depletion (Na+, K+, Mg+, Cl-), GI effects. |
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Term
| Talk about spironolactone. Class of drug? Formulation? Other similar drugs in the class? Uses? Side effects/contraindications? |
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Definition
Potassium-sparing diuretic.
Oral (give with food to reduce GI effects)
Eplerenone.
Often used after CHF becomes refractory to Lasix alone, in combo with Lasix and hydrochlorothiazide.
Can cause azotemia, weakness, dehydration (duh), hypotension, electrolyte depletion (Na+, Mg+, Cl-), GI effects.
Avoid in patients with renal dz. |
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Term
| Talk about hydrochlorothiazide. Class of drug? Formulation? |
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Definition
Thiazide diuretic (inhibits NaCl reabsorption in DT)
Oral (often in tablet with spironolactone) |
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Term
| How are cardiac glycosides helpful in heart failure? Other uses? |
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Definition
Increase Ca++ influx into myocardium by inhibiting Na+K+ATP-ase, resulting in positive inotropy. Also vagomimetic, resulting in negative chronotropy, dromotropy. Restore baroreceptor reflexes toward normal; reduce sympathetic activation.
Used in CHF, also to treat supraventricular tachyarrythmias. |
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Term
| Talk about digoxin. Class of drug? Formulation? Other similar drugs in the class? Side effects? |
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Definition
Cardiac glycoside (positive inotrope; negative chrono- and dromotrope).
IV and oral (digitoxin is oral only)
Narrow therapeutic window!
Side effects: anorexia, depression, salivation, V/D, arrhythmias. |
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Term
| Talk about pimobendan. Class of drug? Formulation? Other similar drugs in the class? Indications? Side effects? |
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Definition
Calcium sensitizer. Increases inotropy by increasing troponin C interaction.
Vasodilation by PDE III inhibition.
Only drug in class.
Chewable tablet; not stable for long when compounded.
Approved for use in CHF due to DCM; valvular dz (also used for other CHF).
Side effects uncommon; may include hyperexcitability. |
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Term
| What 3 drugs are most commonly prescribed to CHF patients? |
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Definition
| Furosemide, ACE inhibitor, pimobendan |
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Term
| What 3 vasodilatory agents are used as cardiac drugs, and how are they similar/different? |
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Definition
Nitroglycerin: works on venous smooth muscle, coronary arteries.
Hydralazine: works on arteries
Sodium Nitroprusside: works on arterial and venous smooth muscle ("balanced vasodilator") |
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Term
| Talk about nitroglycerin. Class of drug? MOA? Formulation? Indications? Cautions/side effects? |
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Definition
Vasodilator. Metabolized to NO; direct dilation of venous and coronary artery smooth muscle.
IV or transcutaneous.
Used to treat pulmonary edema (moves blood from congested pulmonary circulation to systemic veins) and dilate coronary arteries.
Use only 2-3 days (tolerance may develop).
Side effect = headaches. |
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Term
| Talk about hydralazine. Class of drug? Formulation? Uses? |
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Definition
Vasodilator: arterial dilation.
Tablet.
Used for mitral insufficiency, hypertension. |
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Term
| Talk about sodium nitroprusside. Class of drug? MOA? Formulation? Indications? Side effects? |
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Definition
Vasodilator (balanced). Acts via NO.
IV only (short duration of action so must be continuously infused).
Useful in severe pulmonary edema when furosemide is ineffective.
Must be monitored closely due to potency of hypotensive effect. |
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Term
| What are the 4 classes of anti-arrhythmic drugs? |
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Definition
Class I: local anesthetics/Na+ entry blockers
Class II: Beta-blockers
Class III: Action potential-prolonging agents
Class IV: Calcium channel blockers |
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Term
| Talk about procainamide. Class of drug? MOA? Formulation? Other similar drugs in the class? Indications? |
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Definition
Class I anti-arrhythmic: local anesthetic (Na+ entry block stabilizes membranes and decreases AP).
IV, IM, oral.
Lidocaine, quinidine are other drugs in class.
Used for ventricular arrhythmias in small animals.
Monitor QRS duration: increase of >25% indicates toxicity. |
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Term
| Talk about lidocaine. Class of drug? MOA? Formulation? Other similar drugs in the class? Indications? Side effects? |
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Definition
Class I anti-arrhythmic: local anesthetic (Na+ entry block stabilizes membranes and decreases AP).
IV only.
Procainamide, quinidine are other drugs in class.
Used for ventricular arrhythmias in small animals. Quick and safe so popular for stopping arrhythmias in the ER.
Side effects: neurotoxic in cats, horses.
Monitor QRS duration: increase of >25% indicates toxicity. |
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Term
| Talk about quinidine. Class of drug? MOA? Formulation? Other similar drugs in the class? Indications? Side effects? |
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Definition
Class I anti-arrhythmic: local anesthetic (Na+ entry block stabilizes membranes and decreases AP).
IM, oral.
Lidocaine, procainamide are other drugs in class.
Mainstay for ventricular arrhythmias in horses. Especially useful for converting A-fib due to vagolytic action (enhances AV node conduction). Also has alpha-adrenergic blocking properties.
Monitor QRS duration: increase of >25% indicates toxicity. |
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Term
| What is main disadvantage of propanolol compared to atenolol or metoprolol? |
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Definition
| Propanolol is a non-specific beta blocker (binds both B1 and B2 receptors). Thus, it can cause bronchoconstriction and vasoconstriction due to its effects on B2 on smooth muscle. In contrast, atenolol and metoprolol are B1-specific, so their effects are limited to cardiac negative inotropy and chronotropy. |
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Term
| Why do you have to worry about the degree of heart disease in your patient before prescribing a beta blocker or calcium channel blocker? |
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Definition
| In patients with a very limited cardiac reserve (i.e. CO is just about insufficient), the negative inotropic and negative chronotropic effects of these drugs can precipitate heart failure. However, if the patient is caught before a great degree of cardiac remodeling has occurred, these drugs (along with furosemide, ACE inhibitors, and pimobendan) can stop the vicious cycle of hypertension and cardiac fatigue. |
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Term
| Talk about propanolol. Class of drug? MOA? Formulation? Other similar drugs in the class? Indications? Side effects? |
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Definition
Class II anti-arrhythmic: Beta blocker (non-specific).
Blocks B1 and B2 receptors to decrease inotropy and chronotropy (also causes bronchoconstriction, vasoconstriction).
IV, oral.
Atenolol, metoprolol are B1 specific; esmolol is short-acting; carvedilol is an alpha and beta blocker.
Used for supraventricular and ventricular tachycardia, theophylline intoxication, pheochromocytoma, thyrotoxicosis, long-term control of CHF.
Can precipitate HF in patients with little functional reserve. |
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Term
| Talk about atenolol. Class of drug? MOA? Formulation? Other similar drugs in the class? Indications? Side effects? |
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Definition
Class II anti-arrhythmic: Beta blocker (B1-specific).
Blocks B1 receptors to decrease inotropy and chronotropy.
Oral.
Metoprolol is another B1 specific drug; propanolol is non-specific (B1 and B2); esmolol is short-acting; carvedilol is an alpha and beta blocker.
Used for supraventricular and ventricular tachycardia, theophylline intoxication, pheochromocytoma, thyrotoxicosis, long-term control of CHF.
Can precipitate HF in patients with little functional reserve. |
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Term
| Talk about metoprolol. Class of drug? MOA? Formulation? Other similar drugs in the class? Indications? Side effects? |
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Definition
Class II anti-arrhythmic: Beta blocker (B1-specific).
Blocks B1 receptors to decrease inotropy and chronotropy.
Oral.
Atenolol is another B1 specific drug; propanolol is non-specific (B1 and B2); esmolol is short-acting; carvedilol is an alpha and beta blocker.
Used for supraventricular and ventricular tachycardia, theophylline intoxication, pheochromocytoma, thyrotoxicosis, long-term control of CHF.
Can precipitate HF in patients with little functional reserve. |
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Term
| Talk about esmolol. Class of drug? MOA? Other similar drugs in the class? Indications? Side effects? |
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Definition
Class II anti-arrhythmic: Beta blocker
Blocks B1 receptors to decrease inotropy and chronotropy.
Atenolol and metoprolol are B1 specific drugs; propanolol is non-specific (B1 and B2); carvedilol is an alpha and beta blocker.
Esmolol is short acting and is used for some arrhythmias in the ICU.
Like all beta blockers, can precipitate HF in patients with little functional reserve. |
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Term
| Talk about carvedilol. Class of drug? MOA? Formulation? Other similar drugs in the class? Indications? Side effects? |
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Definition
Class II anti-arrhythmic: Beta blocker (non-specific).
Blocks alpha, B1, and B2 receptors to decrease inotropy and chronotropy (also causes bronchoconstriction, vasoconstriction).
Oral.
Propanolol is non-specific (B1 and B2); atenolol and metoprolol are B1 specific; esmolol is short-acting.
Used for supraventricular and ventricular tachycardia, theophylline intoxication, pheochromocytoma, thyrotoxicosis, long-term control of CHF.
Can precipitate HF in patients with little functional reserve. |
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Term
| Talk about sotalol. Class of drug? MOA? Formulation? Indications? |
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Definition
Class III anti-arrhythmic drug: action potential-prolonging agent. Also has beta blocking properties.
Long-term oral therapy for ventricular arrhythmias. |
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Term
| Talk about amiodarone. Class of drug? MOA? Formulation? Half-life? Indications? Side effects? |
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Definition
Class III anti-arrhythmic drug: action potential-prolonging agent. Also has some properties of Classes I-IV.
IV and oral. Very long half life.
Long-term oral therapy for ventricular arrhythmias.
Many side effects; hard to use. |
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Term
| What is the MOA of calcium channel blocking drugs? |
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Definition
Inhibit Ca++ influx into contractile and conductile myocardial cells AND vascular smooth muscle cells. Causes negative inotropy, dromotropy, and vasodilation.
Used for supraventricular tachycardias, HCM.
Like beta blockers, can precipitate heart failure in patients with little functional reserve. |
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Term
| Talk about verapamil. Class of drug? MOA? Formulation? Other drugs in class? Uses? Cautions? |
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Definition
Class IV anti-arrhythmic drug: calcium channel blocker.
Negative inotrope, dromotrope, vasodilator.
IV, oral.
Diltiazem is another drug in the class, as well as amlodipine.
Used for supraventricular tachycardias, HCM.
Like beta blockers, can precipitate heart failure in patients with little functional reserve. |
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Term
| Talk about diltiazem. Class of drug? MOA? Formulation? Other drugs in class? Uses? Cautions? |
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Definition
Class IV anti-arrhythmic drug: calcium channel blocker.
Negative inotrope, dromotrope, vasodilator.
IV, oral.
Verapamil is another drug in the class, as well as amlodipine.
Used for supraventricular tachycardias, HCM.
Like beta blockers, can precipitate heart failure in patients with little functional reserve. |
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Term
| Talk about amlodipine. Class of drug? MOA? Formulation? Other drugs in class? Uses? Cautions? |
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Definition
Class IV anti-arrhythmic drug: calcium channel blocker.
Negative inotrope, dromotrope, vasodilator.
Oral.
Verapamil and diltiazem are other drugs in the class.
Used for supraventricular tachycardias, HCM, and systemic hypertension. |
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