Cardiovascular Flashcards
What are the catecholamine B1- agonists?
Epinephrine Norepinephrine Dopamine Dobutamine Isoproterenol
What two drugs are methylxanthines?
Aminophylline
Theophylline
What is the MOA of aminophylline ?
Phosphodiesterase (PDE) inhibition -> increase the amount of cAMP-> increase release of endogenous epinephrine
What is the main effect of aminophylline and theophylline?
Bronchodilation
- direct relaxation of smooth muscle in bronchi and pulmonary vasculature
- some centrally mediated respiratory stimulation
Weak chronotrope and inotrope
(Usually considered a side effect)
What are precautions to treating with aminophylline/theophylline?
Patient with cardiac disease or hypertension
->tachycardia
Seizure disorder Gastric ulcer Hyperthyroidism Severe hypoxia Renal or hepatic dysfunction
What are used in the treatment of congestive heart failure ?
Positive inotrope Vasodilator Inodilator (both positive inoptropic and vasodilator effects) Diuretics Beta blockers
What is the body’s normal compensatory mechanisms for congestive heart failure?
In response to decreased blood pressure:
- Increase sympathetic tone
- ADH secretion
- RAAS activation
Myocardial remodeling
What to drugs are positive inotropes?
Digoxin
B-1agonsit (eg Dobutamine)
What is the MOA of digoxin?
Inhibit Na/K/ATPase in the myocardial cell membrane to increase sodium available for exchange for calcium
-> increase intracellular calcium -> positive inotropic effect
Digoxin is administered ________ most commonly, but is also available in _________
Orally; IV formulation
How is digoxin metabolized and excreted?
Small amount in liver
Enterohepatic recirculation
Dog and horse - renal excretion
Cat- renal and hepatic excretion
What drug has positive inoptropic effects but will reduce sinus rate/nodal conduction?
Digoxin
What should you see on a ECG of a patient on digoxin ???
Prolonged PR interval
-negative chronotropic/dromotropic effects
What are secondary effects/precautions of digoxin?
Renal- diuretic effect due to increase CO (cardiac diuretic)
GI irritation
Vomiting, nausea, anorexia
Diarrhea
Alter serum potassium
Acute-> hyperkalemia
Chronic-> hypokalemia
Tachycardia
What is the number one adverse effect of digoxin???
GI signs
What are factors that predispose a patient to digoxin-induced tachyarrhythmias?
HYPO kalemia / magnnesemia
HYPER calcemia / natremia
HYPER or HYPO thyroidism
Hypoxemia
How do you treat Digoxin toxicity???
Potassium supplementation
Anti-arrhythmic drugs as indicated
Cholestyramine -> decrease enterophepatic recirculation
Digibind -> specific antidote of a digoxin immune Fab
What are the clinical uses of digoxin?
Atrial fibrillation/flutter
Congestive heart failure -> not first line anymore
Pimobendan in a ________ type of drug
Inodilator
What is the MOA of primobendan?
Sensitize myocardial contractile apparatus to calcium-> result in positive inotropic effect
-Enhance interaction between calcium and troponin complex
Phosphodiesterase (PDE)III inhibitor -> result in vasodilator effect
How is pimobendan administered?
Oral absorption is rapid with 60% oral bioavailability
NO IV formulation
Dosed BID or TID
How is pimobendan excreted?
Feces
What is the most common side effect of pimobendan?
GI signs
-vomiting, inappetence, diarrhea
What are side effects associated with pimobendan??
GI signs
Seizure
PU/PD/
Arrhythmia (but less than digoxin)
When is use of pimobendan contraindicated?
Aortic stenosis or any condition where augmentation of cardiac output is inappropriate for function or anatomic reasons
What is considered the drug of choice for treatment of congestive heart failure?
Pimobendan
T/F: pimobendan is an inodolator by increasing intracellular calcium available for exchange with sodium
F
Inodilator through myocardial sensitization to calcium and PDE III inhibitor
Digoxin should not be used concurrently with ___________
Furosemide
_____________ is an abnormality in heart rate and rhythm
Arrhythmia
Anything that is not a normal sinus rhythm