Vasodilators Flashcards
Which vasodilator is used for hypertensive emergencies
Sodium nitropusside
venous and arterial dilation
Sodium nitropusside can cause marked hypotension. What should you give with it
Give with Dobutamine
Which drugs are indicated in CHF secondary to mitral or aortic valve insufficiency
Hydralazine
Minoxidil
Which species is hyralazine commnly used in? Discuss admin/metabolism and excretion
Dogs
Admin: oral - rapid absorption
Metabolism: liver
Excretion: kidneys
Is hydralazine safe to use in uremic patients
No - high concentrations
Side effect hydralazine
Tachycardia
Sodium nitropusside causes the release of what, resulting in vasodilation
Nitrous oxide
What do phosphodiesterase V inhibitors do? Example?
Inhibit cGMP degradation
Sildenafil
Which a1 agonist provides vasodilation with minimal reflex tachycardia
Prazosin
Which vasodilator has a good combo with Digoxin
Prazosin - pos. inotrope effect (Digoxin) and peripheral vasodilaton
Which vasodilator gives marked relaxation of large veins
Nitroglycerine
Which vasodilator is given sublingual for angina *
Nitroglycerine
Describe topical use of nitroglycerine in dogs and horses
Topical ointment 2%
Dogs:
- for cardiogenic pulmonary edema
Horses
- for acute laminitis
Which vasodilator acts on skeletal muscle vessels
Isoxsuprine (b2 agonist)
Which vasodilator is indicated in laminitis and navicular disease (horses)
Isoxsuprine
Administration Isoxsuprine
Powder to feed/oral paste
Calcium channel blockers for vasodilation
Diltiazam
Amlodipine
Indications of Diltiazam
Hypertrophic cardiomyopathy in dogs and cats
Indications of amlodipine
Hypertension in cats
Which calcium channel blocker is commonly used in vet med and has few significant cardiac effects
Amlodipine
What;s important about ACE inhibitor dosing
Theres a threshold limit which you cant exceed even with increased dose
What effect do NSAIDs have on ACE inhibitors
Decrease their hypotensive effect
MOA Ace Inhibitors
- Vasodilation (decreased Ang-2 and decrease Ang-2 receptors)
- Reduce sympathetic outflow of brain
- Potassium sparing effect
Excretion ACE inhibitors
Kidney
*Caution with renal disease*
Are ACE inhibitors safe for patients with renal disease
No - take caution
ACE inhibitors (4)
‘Elan Likes Ben’s Cat’
1. Catopril
2. Lisinopril
Prodrugs
3. Enalpril
4. Benazepril
Which ACE inhibitor comes from pit viper venom
Catopril
T/F - its preferred to give Catopril with food
False - bioavailability decreases with food
Which is most potent ACE inhibitor
Lisinopril
Which ACE inhibitor’s bioavailability is not affected by food *
Benazepril
Which ACE inhibitor is an alternative to Digoxin in mild CHF? What should you administer before
Enalpril
Give diuretics before
T/F ACE inhibitors are safer in patients with ischemic heart disease
True
Indications of ACE Inhibitors (2)
- Heart failure
- Hypertension
T/F - ACE Inhibitors have potassium sparing effect. Explain
True - due to:
- Decrease Na/K exchange in CD
- Decrease secretion of aldosterone
Angiotensin receptor blockers
Losartan
Irbesartan
Indications for Losartan and Irbesartan
(Angiotensin receptor blockers)
- Hypertension
- Heart failure
* Doesnt alter Bradykinin activity*
MOA of Losartan and Iberartan
Block angiotensin receptor –> no vasoconstriction
3 Objectives of treating Left Ventricular Failure
- Improve gas exchange —> give O2
- Enhance myocardial contractility –> give Dobutamine
- Reduce workload of LV –> give Furosemide
What do you give patients to relieve dyspnea and anxiety with heart failure? How does it work
Morphine Sulphate
- Hypotensive effect*
- Decreases response of medullary resp center to increase pCO2*
You have a dog with pulmonary edema from LV failure. What do you give as maintenance therapy after treating acute condition
Digoxin
T/F - Epinephrine is beneficial in LV failure
FALSE – CONTRAINDICATED!
Your patient is in left ventricular failure with pulmonary congestion. What can you give immediately to help? How does it work
Furosemide
Loop diuretic —> increases venous capitance –> decreased pulmonary congestion
Which phosphodiesterase inhibitors are preffered for myocardial failures? Which for pulmonary hypertension?
Class III: myocaridal failures (aminophylline, inamrinome, pimobendan)
Class V: pulmonary hypertensuion (sildenafil)
