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Flashcards in Chapter 7 - Drugs mentioned during lecture Deck (24):


- Anti-cholinergic
- raises HR by blocking parasympathetic nervous system's tendency to lower HR
- be careful when giving this, you lost the HR as a monitoring tool during anesthesia



- Anti-cholinergic
- raises HR by blocking parasympathetic nervous system's tendency to lower HR
- be careful when giving this, you lost the HR as a monitoring tool during anesthesia
- Stays around longer than Atropine



Opens up arterioles (vasodilator)


Compensatory mechanisms of the CV system

1. Increasing HR
2. Increasing SV
3. Increasing the efficiency of the heart muscle
4. Cardiac remodeling


Chronotropic drugs

Increase or decrease HR to make CO more efficient


Inotropic drugs

Increase or decrease the mycardial wall tension and SV to normalize CO and cardiac O2 consumption


Dromotropic drugs

Stabilize the electrical conduction system of the heart


Define hypertrophic and dilated cardiomyopathy

enlarged muscle, ineffective pump (seen lots in cats)
heart is a great big paperbag; not efficient; low SV; blood slushes around in heart (taurine can help w/dilated cardiomyopathy)


Define mitral insufficiency

Blood being ejected from the left ventricle back into the atrium.
Sodium and water retention, increased SV, increased heart muscle follow.


Mixed inotrope/chronotrope/dromotrope

Cardiac Glycosides (Digoxin and digitoxin)
- derived from the dried leaves of the plant Digitalis purpurea
- Useful for atrial fibrillation, supraventricular tachycardia (current choice Ca channel blockers)
- also used for CHF (current choice ACE inhibitors and diuretics)
- Narrow therapeutic index, therefore no longer drug of choice
- Must monitor blood drug levels and perform ECG


Name three inotropes

1. Epinephrine
- raises BP, HR, and SV
- rescue drug; ER crisis of asystole
- mixed alpha & beta activity
- if it has an adrenergic receptor, it hits it
2. Dopamine
- given by drip to increase BP, HR, and SV
- Alpha 1 and beta 1 receptors
- constricts vasculature w/o affecting heart too much
3. Dobutamine
- not used often
- increases SV & CO without vasodilation
- works on heart (beta 1 receptors)


Name the current drug of choice for canine CHF

Pimobendin (Vetmedin)
- Inodilator (inotropic, mixed dilator); dual action of +inotrope and mixed vasodilation
- better SV; less peripheral vasculature resistance; better tissue perfussion; increased venous return
- does not increase mycardial oxygen consumption
- good therapeutic index
- may be used for MI
- side effects are minimal (or tolerable)
- expensive


Name the ACE inhibitors

The "prils":
Benazepril (LoTensin)
Enalapril (Enacard)
Lisenopril (given SID - little more friendly)
- These are considered antihypertensives
- They inhibit angiotensin I from being converted to angiotensin II


What does ACE stand for?
And what does it do?

= Angiotensin converting enzyme
It converts angiotension I into angiotensin II, releasing aldosterone thereby increasing intervascular volume (as water follows salt and aldosterone is known as the salt keeper)


Name a calcium channel blocker

Cardizem LA (long-acting)
- Antihypertensive
- interferes w/transport of calcium
- increases coronary circulation w/peripheral artery dilation


What drug can control blood/vascular volume?

- A diuretic like furosamide (Lasix - sodium losing loop diuretic), or Spironolactone (diuretic sparing K)
However, restriction of sodium intake through dietary changes can control blood volume as well. Many petfoods & treats are over 1% NaCl. Client education is key!


Before trying Pimobendin, what else could you try to reduce BV in CHF?

Salt restriction in conjunction w/ACE inhibitors


Define afterload

Resistance of tissue to forward flow of blood (after ventricular contraction)


Name afterload reducers

*Pimobendin (Vetmedin)
*Prazosin (Minipress), comes as cream or capsules; potent venodilator
*Sildenafil (Viagra) for pulmonary hypertension


How to manage acute ventricular arrhythmia?

*Procaineamide - lasts longer than lidocaine
*Lidocaine w/o epinephrine - will put electric instability in heart to rest


Lidocaine comes in several doses. Name a few!

*Lidocaine w/epinephrine = lasts longer, but not for crash card
*Lidocaine w/o epinephrine = IV use for crash cart
*Lidocaine w/o epinephrine and preservatives = good for epidurals


SA node stabilizers

Sotalol (Betapace)


Ventricular antipacing to reduce HR

*Propanalol (Inderal) - beta adrenergic blocker
*Digoxin (Lanoxin) - Glycosides
*Diltiazem (Cardizem) - Calcium channel blocker


Anti-coagulation drugs

*Aspirin - platelet stickiness inhibitor
*Clopidogrel (Plavix) - platelet aggregation inhibitor
*Coumarin - inhibits Vit K for longer term anticoagulation effects