Norepinephrine/Noradrenaline dosing equivalence

Gist: Expression of norepinephrine/noradrenaline dosing is not standardized across countries

Formulations:

• noradrenaline tartrate (European Pharmacopoeia)
• noradrenaline acid tartrate (British Pharmacopoeia)
• norepinephrine bitartrate (United States Pharmacopeia)

All formulations are equivalent in vasopressor potency (only difference is a H2O molecule added in bitartrate).

Equivalence: 2 mg of norepinephrine bitartrate/tartrate are equivalent to 1 mg of norepinephrine base

Issue: dosing can be expressed as norepinephrine base or specific formulation (e.g. norepinephrine tartrate)

• North America: norepinephrine base is the most common expression of dosing
• Europe: norepinephrine tartrate is the most common expression of dosing (but very variable across countries)

Thus expression of dosing in Europe is often erroneously twice as high as if expressed in North America. Therefore, caution is required when applying norepinephrine dosing across settings.

Refs:

1. Leone, M., Goyer, I., Levy, B. et al. Dose of norepinephrine: the devil is in the details. Intensive Care Med 48, 638–640 (2022). https://doi.org/10.1007/s00134-022-06652-x

Sole difference between noradrenaline tartrate and norepinephrine bitartrate is the extra water molecule in norepinephrine bitartrate