Final Flashcards
anything that has a catechole and an amine group
Naturally occurring catecholamines
Pharmacologic effects of sympathomimetics:
- Vasoconstriction (Cutaneous and renal circulations)
- Vasodilation
- Bronchodilation
- Cardiac stimulation (^HR, ^Contractility, ^dysrhythmias)
Clinical use of sympathomimetics
- Positive inotropes to improve cardiac contractility.*
- Vasopressor to elevate blood pressure from unacceptable low levels
- Treatment of bronchospasm in the asthmatic patient. Inhaled sympathomimetics
- Management of anaphylaxis
The only time a vasopressor should be used is when the patient’s blood pressure must be increased __________ to avoid pressure-dependent reductions in organ perfusion with subsequent ischemia
immediately
catecholamine drug vs non-catecholamine difference is ______ only
structure
Epinephrine
Potent activator of alpha-adrenergic receptors
Also activates beta-1 and beta -2 receptors
Norepinephrine
Most affinity for A1 effects
No B2
Has some b1 effects, but not great
Main increase on peripheralVR
HR may go down a bit since B1 not significant due to reflex response of body
Dopamine
Acts via PRESYNAPTIC dopamine-1 receptors
- 1-2ug/kg/min vasodilation of renal vasculature
- 2-10ug/kg/min beta-1 receptors in the heart
- > 10ug/kg/min alpha receptors in the peripheral vasculature
Synthetic Catecholamines
isoproteronol
dobutamine
Isoproterenol
- Most potent activator of beta-1 and beta-2 receptors (2-10 times greater than epinephrine, 100 times greater than norepinephrine)
- In clinical doses, isoproterenol is devoid of alpha agonist effects
- causes tachyarrhythmias
dobutamine
doButamine – Beta
More selective for b1
Useful to improve cardiac output in patients in cardiac failure, especially if heart rate and peripheral vascular resistance are elevated.
Uses for isoproterenol
bronchodilation
increase heart rate in the presence of complete heart block
decrease pulmonary vascular resistance in patients with pulmonary hypertension
Synthetic Noncatecholamines: direct and non-direct
Indirect-Acting (can bind to A and B receptors, but effects come from release of norepi)
-Ephedrine
Direct Acting
-Phenylephrine
Ephedrine
Norepi effects:
- Most affinity for A1 effects
- Has some b1 effects, but not great
Plus B2 effects
- Acts on alpha and beta-adrenergic receptors
- Also has direct acting stimulant effects on adrenergic -receptors
Phenylephrine
All Alpha effects in treatment doses – low pressure but already tachycardic – give phenylephrine
Causes reflex vagal effects (decreased HR). (may result in a decreased CO)
Renal, splanchnic, and cutaneous blood flow is reduced
Coronary blood flow is increased.
Pulmonary arterial pressure is elevated.
