Cardiovascular Drugs Flashcards
What are 2 things a positive inotrope does?
- Increase cardiac output
- Increase atrial filling pressure
Adrenergic agonists help to maintain what?
Prevent what?
- Maintain arterial blood pressure
- Prevent tissue ischemia
When vasopressors are administered what occurs to heart rate?
Slows heart rate
Adrenergic agonists are not recommended in the face of what?
Hypovolemia
What are 2 examples of adrenergic agonists?
- Bronchospasm (asthma)
- Life threatening allergic reactions
What are 3 possible routes of administration for adrenergic agonists?
What is not an effective route?
- SQ, IV, Intra-tracheal
- Oral
What is are 3 examples of a drug that is an A1, A2, B1, B2 agonist?
- Epinephrine
- Norepinephrine
- Ephedrine
What effect does epinephrine have on heart rate?
On vascular tone?
- Increases HR
- Increases vascular tone (vasoconstriction)
What is the strongest vasopressor that can be administered during cardiopulmonary arrest?
Epinephrine
Is epinephrine the go to drug for hypotension?
Why?
- No
- Can be potent tachyogenic drug. Also potent vasoconstrictor which decreases organ profusion
What are 2 indications for epinephrine?
- Treat life-threatening allergic reactions
- CRI in non-responsive hypotension
Epinephrine decreases what?
Renal blood flow
Epinephrine increases what 6 things?
- Blood pressure
- Peripheral vascular resistance
- Myocardial contractile force
- Heart rate
- Cardiac output
- Bronchodilator
What are 4 disadvantages of epinephrine?
- Severe vasoconstriction can lead to decrease perfusion of tissues
- Increase in oxygen consumption (increased cardiac work)
- Can induce ventricular fibrillation (tachyarrhythmias)
- Increase sensitivity to tissue hypoxia
Epinephrine should be left for what?
Resistant hypotension or CPA
Does norepinephrine produce more or less severe tachycardia than epinephrine?
Less severe tachycardia
What is norepinephrine used for?
Significant non-responsive hypotension
Do you usually use norepinephrine with cardiac arrest?
No
What does norepinephrine decrease?
Renal blood flow
What are 4 things increased by norepinephrine?
- Blood pressure
- Peripheral vascular resistance
- Myocardial contractile force
- Heart rate
What is an example of an A1, B1, B2 agonist?
Dopamine
What are 2 indications for dopamine?
- Treatment of hypotension
- Increase urine output
What does dopamine decrease?
Partial pressure of oxygen in blood (interferes with ventilatory response)
What are 4 things dopamine increases?
- Myocardial contractility
- Renal blood flow
- Glomerular filtration rate
- Systemic vascular resistance (only seen with high dose)
How does dopamine need to be administered?
As a CRI
What is a low dose of dopamine?
What is seen with a low dose?
- 1-4 ug/kg/min
- Stimulates dopamine receptors
What are 4 results of dopamine receptor stimulation?
- Splanchnic vasodilation
- Natriuresis
- Diuresis
- Alterations in renal & GI blood flow
What is natriuresis?
Excretion of sodium in the urine
What is diuresis?
Increased discharge of urine
What is a medium dose of dopamine?
What are 2 things seen with a medium dose?
- 5-10 ug/kg/min
- Increase HR/contractility, mild change in vascular resistance
What is a high dose of dopamine?
What are 2 things seen with a high dose?
- Increase vascular resistance
- Increase contractility/HR
Mainly beta and only mild alpha effects are seen with which type of dopamine dose?
Medium dose
Dopamine receptors are stimulated with which type of dopamine dose?
Low dose
Significant beta and alpha effects are seen with which type of dopamine dose?
High dose
What type of agonist is dobutamine?
Non-specific Beta agonist
Which drug is a common choice for equine hypotension?
Dobutamine
What is dobutamine used for?
Treatment for hypotension
What are 2 things increased by dobutamine?
- Contractility
- HR
What are 4 side effects seen with dobutamine?
- Tachycardia
- Arrhythmias
- Vasodilation
- Seizures/tremors (cats at doses > 5ug/kg/min)
What type of an agonist is isoproterenol?
Beta agonist
What is the main clinical use of isoproterenol?
Treatment 3rd degree heart block
What are 3 effects isoproterenol has?
- Increase HR (can cause significant tachycardia)
- Potent inotrope
- Potent chronotrope
Is isoproterenol still commonly used?
No
What are 3 side effects seen with isoproterenol?
- Arrhythmias
- Tachycardia
- Hypotension
What type of agonist is phenylephrine?
Alpha 1 agonist
What are 4 clinical uses of phenylephrine?
- Significant vasoconstriction
- Splenic contraction
- Decrease epistaxis
- Decrease nasal edema
What are 2 side effects seen with phenylephrine?
- Decreased blood flow
- Decreased cardiac output (increased afterload, reflex bradycardia)
Caution should be used when using phenylephrine in what species?
Why?
- Horses
- Decrease in blood flow to GIT
High doses of phenylephrine have potential for what?
Some Beta effects
How is phenylephrine administered?
As a CRI
What are 2 clinical uses for ephedrine?
- Treatment of hypotension
- Increase cardiac output
What are 3 effects of ephedrine?
- Increase HR
- Increase vascular resistance
- Increase contractility
Which drugs are used routinely for the treatment mild of hypotension?
- Ephedrine
- Dopamine
- Dobutamine
- Phenylephrine
Which drugs are used routinely for the treatment of moderate hypotension?
- Phenylephrine
- Norepinephrine
Which drugs are used for the treatment of severe hypotension?
- Vasopressin
- Epinephrine
Does ephedrine have a slow or fast onset?
Fast onset
What can ephedrine cause?
CNS excitement
Which cardiovascular drug is not given CRI?
Ephedrine
Which 2 drugs are mainly or only non-selective beta agonists?
- Mainly: dobutamine
- Only: isoproterenol
What are 3 clinical uses for vasopressin?
- Treatment during CPA (cardiopulmonary arrest)
- Vasodilatory shock
- Von Willebrand disease (stimulates platelets and bone marrow)
Which is better for the treatment of CPA, epinephrine or vasopressin?
Vasopressin
What are 4 side effects of vasopressin?
- Decrease tissue perfusion
- Contraction (bladder, gall bladder)
- Local irritation at injection site
- Skin necrosis (extravasation)
What are the 3 steps in the treatment of hypotension in order?
1) Check anesthetic depth
2) Check volume status
3) Administer CV drugs
What can cause hypotension in regards to anesthetic depth?
What should be done?
- Too deep
- Decrease anesthetic
What are 3 things that can be done if patient has a low volume status causing hypotension?
- Administer fluid bolus
- Increase fluid rate
- Change to more appropriate fluid choice
What can be given to treat an ephedrine overdose that has caused ventricular tachycardia?
1-2 mg/kg lidocaine
What is used to treat ventricular tachyarrhythmias by reducing cellular excitation?
Lidocaine
When treating a hypertensive emergency, the MAP should be reduced by no more than what?
25% within minutes to 1 hour
Excessive falls in arterial blood pressure can lead to what?
Renal, cerebral and coronary ischemia
Nitroprusside CRI causes what?
Arterial & venous dilation
Nitroprusside CRI can’t be used longer than what time period?
Why?
- 24 hours
- Cyanide can build up
Hydralazine can cause what?
This can lead to what?
- Arterial vasodilator
- Profound hypotension
What is enalaprilat?
ACE inhibitor
What is a class of drugs that will slow down heart rate?
Beta blockers
What are 3 drugs that can be used to treat hypertension?
- Nitroprusside CRI
- Hydralazine
- Enalaprilat
What are 3 examples of negative dromotropic agents?
- Diltiazem
- Esmolol
- Adenosine
What does a dromotropic agent do?
Decreases conduction of electrical impulses to the heart.
What are 2 indications for the use of temporary transvenous pacing?
- Support HR & BP while under general anesthesia for permanent pacemaker
- Refractory bradycardia stabilization prior to pacemaker implantation
What type of cardiac disorder do we commonly apply transvenous pacing?
Severe 3rd degree AV block
