Metaraminol
Metaraminol, also known as metaradrine and sold under the brand name Aramine among others, is a sympathomimetic medication which is used in the prevention and treatment of hypotension, particularly as a complication of anesthesia. It is given by intramuscular or intravenous administration.
Side effects of metaraminol include reflex bradycardia among others. Metaraminol is a norepinephrine releasing agent and at high doses a α1-adrenergic receptor agonist with some β-adrenergic effect. It is a substituted amphetamine and is closely related to phenylpropanolamine, ephedrine, and oxilofrine.
Metaraminol was approved for medical use in the United States in September 1954.
Medical uses
Metaraminol is given intravenously as either a bolus or as an infusion, usually via peripheral intravenous access. Metaraminol is commonly available as 10 mg in 1 mL, that requires dilution prior to administration, however pre-prepared syringes of metaraminol for bolus use for hypotension are also commonly available.Metaraminol is also used in the treatment of priapism.
Pharmacology
Pharmacodynamics
The dominant mechanism of action for the vasopressor action of metaraminol is indirect, with metaraminol displacing norepinephrine from neuronal vesicles in order for the noradrenaline to exert these effects. Metaraminol at higher doses may have direct α-adrenergic agonist and β1-adrenergic agonist effects. However at doses common in clinical practice, the indirect α1-adrenergic effects predominate, such that reflex bradycardia is a common side effect.Chemistry
Metaraminol, also known as -3,β-dihydroxy-α-methylphenethylamine or as -3,β-dihydroxyamphetamine, is a substituted phenethylamine and amphetamine derivative. It is the -enantiomer of meta-hydroxynorephedrine. The drug is closely related to phenylpropanolamine, ephedrine, para-hydroxynorephedrine, and oxilofrine.The experimental log P of metaraminol is -0.27 and its predicted log P ranges from -0.59 to 0.07.
Metaraminol is used pharmaceutically as the bitartrate salt.