Metaraminol, previously sold under the brand name Aramine among others and also known as metaradrine, is a stereoisomer of meta-hydroxynorephedrine (3,β-dihydroxyamphetamine), is a potent sympathomimetic amine used in the prevention and treatment of hypotension, particularly as a complication of anesthesia. It is an α1-adrenergic receptor agonist with some β-adrenergic effect.[2] It is currently sold in its generic form by Slayback Pharma.[3]

Pharmacology and use as a vasopressor

Metaraminol is given intravenously as either a bolus (often 0.5–1 mg doses) 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 (often made up to a 0.5 mg/mL solution), however pre-prepared syringes of metaraminol for bolus use for hypotension are also commonly available.[4][5]

A commercially prepared pre-filled syringe of metaraminol for bolus use during anaesthesia, made up as 0.5 mg/mL (2.5 mg in 5 mL).

Pharmacodynamics

The dominant mechanism for the vasopressor action of metaraminol is indirect,[6] with metaraminol displacing noradrenaline from neuronal vesicles in order for the noradrenaline to exert its vasopressor action.[7] Metaraminol at higher doses may have direct alpha-adrenergic agonist and β1 adrenergic agonist effects.[6] However at doses common in clinical practice, the indirect α1 adrenergic effects predominate, such that reflex bradycardia is a common side-effect.

Research

Metaraminol is also used in the treatment of priapism.[8][9][10]

References

  1. ^ "Injection : Aramine (Metaraminol Bitartrate)" (PDF). U.S. Food and Drug Administration (FDA). Retrieved 12 March 2022.
  2. ^ Kee VR (August 2003). "Hemodynamic pharmacology of intravenous vasopressors". Crit Care Nurse. 23 (4): 79–82. doi:10.4037/ccn2003.23.4.79. PMID 12961786.
  3. ^ "ANDA Approval for Metaraminol" (PDF). United States Food and Drug Administration. 24 August 2021. Retrieved 13 August 2022.
  4. ^ "Metaraminol 0.5 mg/ml, Solution for Injection in pre-filled syringe - Summary of Product Characteristics (SmPC) - (emc)". www.medicines.org.uk. Retrieved 19 October 2022.
  5. ^ Goodrick N, Wentrup T, Messer G, Gleeson P, Culwick M, Goulding G (21 August 2020). "Pre-filled emergency drugs: The introduction of pre-filled metaraminol and ephedrine syringes into the main operating theatres of a major metropolitan centre". Australasian Anaesthesia (2013): 127–134.
  6. ^ a b "Metaraminol". Deranged Physiology. Retrieved 19 October 2022.
  7. ^ Harrison DC, Chidsey CA, Braunwald E (September 1963). "Studies on the Mechanism of Action of Metaraminol (Aramine)". Annals of Internal Medicine. 59 (3): 297–305. doi:10.7326/0003-4819-59-3-297. PMID 14065947.
  8. ^ McDonald M, Santucci R (2004). "Successful management of stuttering priapism using home self-injections of the alpha-agonist metaraminol". Int Braz J Urol. 30 (2): 121–2. doi:10.1590/S1677-55382004000200007. PMID 15703094.
  9. ^ Koga S, Shiraishi K, Saito Y (1990). "Post-traumatic priapism treated with metaraminol bitartrate: case report". J Trauma. 30 (12): 1591–3. doi:10.1097/00005373-199012000-00029. PMID 2258979.
  10. ^ Block T, Sturm W, Ernst G, Staehler G, Schmiedt E (1988). "[Metaraminol in therapy of various forms of priapism]". Urologe A. 27 (4): 225–9. PMID 3140463.

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