Understanding Anesthesiology - The Global Regional Anesthesia ...

Ephedrine Sulfate
Class
Sympathomimetic (indirect-acting); vasopressor. Used in the treatment of hypotension.
Mechanism of Action
Ephedrine causes more norepinephrine to be released from the storage vesicles in the terminal
of neurons thus increasing the amount of norepinephrine in the synaptic space. Ephedrine
is (mostly) an “indirect-acting” catecholamine because it doesn’t act at the post-synaptic
norepinephrine receptors.
Dose
5-20 mg IV (adults)
25-50 mg IM (adults)
Onset
IV: immediate
IM: minutes
Duration
IV: 10-minutes
IM: 60 minutes
Elimination
Hepatic, renal
Effects
CNS
Increases MAC of volatile anesthetics
Respiratory
Bronchodilator
CVS
Increases heart rate, contractility and therefore cardiac output (through its & adrenergic effect).
Overall effect is to increase systemic vascular resistance through its #-adrenergic effect.
May cause arrhythmias especially when used with volatile anesthetics. As the mechanism of
action involves the release of intracellular catecholamines, there is an unpredictable effect in
patients with depleted endogenous catecholamines.
Misc.
Excessive catecholamine effects may lead to hypertension, tachycardia, arrhythmias, pulmonary
edema, anxiety, tremors, hyperglycemia and transient hyperkalemia followed by hypokalemia.
Skin necrosis may occur at site of injection.
Contraindications
Ephedrine should not be used in patients on monoamine oxidase inhibitors (MAOIs) or those
using cocaine. In these patients, phenylephrine is a safer choice for raising blood pressure.
Ephedrine should be used with caution in patients who take SSRIs (serotoninnorepinephrine
re-uptake inhibitors), as it may increase the risk of “serotonin syndrome”.
Related Glossary Terms
Autonomic nervous system, Epinephrine, Phenylephrine, Sympathetic nervous system
Index
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Chapter 6 - Drug Finder
Chapter 6 - Vasoactive Agents