Medication Summary
The goals of pharmacotherapy are to reduce morbidity and prevent complications.
Vasodilators
Class Summary
Vasodilators decrease preload and/or afterload.
Nitroglycerin sublingual (Nitrostat)
This agent causes relaxation of vascular smooth muscle by stimulating intracellular cyclic GMP; the result is a decrease in blood pressure. Dosage forms include SL, TD, and IV preparations. The distinction between short-acting preparations for treatment of acute attacks and long-acting preparations for prevention of recurrent episodes is important.
Administration of 300-400 µg of sublingual nitroglycerine) in order to increase average heart rate by approximately 20-25% over baseline to trigger abnormal responses in susceptible patients after a tilt stabilization phase of 5 minutes. [4]
Beta1/Beta2 Adrenergic Agonists
Class Summary
When given systemically, isoproterenol stimulates beta receptors in the heart, which produces positive inotropic and chronotropic effects. This results in increased cardiac output.
Isoproterenol (Isuprel)
Isoproterenol has sympathomimetic effects; specifically, beta1- and beta2-adrenergic receptor agonist activity.
Intravenous medication used in incremental doses (usually 3 µg/min) in order to increase average heart rate by approximately 20-25% over baseline to trigger abnormal responses in susceptible patients after a tilt stabilization phase of 20 minutes. [4]
Isotonic Crystalloids
Class Summary
Isotonic sodium chloride (normal saline [NS]) is a standard crystalloid intravenous (IV) fluid used for initial volume resuscitation. It expands the intravascular and interstitial fluid spaces. Typically, about 30% of administered isotonic fluid stays intravascular; therefore, large quantities may be required to maintain adequate circulating volume.
Normal saline (NS, 0.9% NaCl)
NS restores interstitial and intravascular volume. Administer a 250-mL bolus of 0.9% NaCl for hypotension.
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Patient undergoing upright tilt-table testing.
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Tilt-table test.