Isoproterenol
Trade names: Isuprel
Class: Sympathomimetic Pregnancy:
(Category C) Action:
§
Isoproterenol is a
synthetic catecholamine that stimulates both beta1 and beta2 adrenergic
receptors
§
(No alpha receptor
capabilities).
§
Inotropic
Sympathomimetic ' non selective beta agonist '
§
The drug affects the heart
by increasing Inotropic and chronotropic activity.
§
In addition, isoproterenol
causes arterial and bronchial dilation, and is sometimesadministered via
aerosolization as a bronchodilator to treat bronchial asthma and bronchospasm.
Indications
§
Hemodynamically significant
bradycardia unresponsive to atropine, TCP, dopamine and epinephrine.
§
Management of torsades de
pointes. (it refers to a specific variety of ventricular
tachycardia that exhibits distinct characteristics on the electrocardiogram).
Contraindications
§
Hypotension (non-rate
related).
§
Cardiac arrest.
§
Ischemic heart disease.
Adverse Reactions
§
Dysrhythmias
§
Hypotension
§
Precipitation of angina
§
Facial flushing
Drug Interactions
§
MAO inhibitors and
bretylium potentiate the effects of catecholamine.
§
Beta adrenergic antagonists
may blunt Inotropic response.
§
Sympathomimetic and
phosphodiesterase inhibitors may exacerbate dysrhythmia response.
Dose:
Adult
Infusion: 2-10
mcg/min titrated to increase HR and perfusion. Typical preparation:
dilute 1 mg in 250 ml for a concentration of 4mcg/ml)
Pediatric
Infusion: 0.5
mcg/kg/min titrated to increased HR and perfusion. Typical preparation:
dilute 0.6 mg/kg to create 100 ml solution.
Nursing Considerations
§
Isoproterenol increases
myocardial oxygen demand, and can induce serious dysrhythmia (including VT and
VF). So deal with it with caution and monitor always for adverse effects.
§
Administer via infusion
pump to ensure precise flow rates.
§
May exacerbate
tachydysrhythmias due to digitalis toxicity or hypokalemia.
§
Newer Inotropic agents have
replaced isoproterenol in most clinical settings.
§ If electronic pacing is available, it should be used instead of
isoproterenol, or as soon as possible after the drug has been initiated.
