Way A Drug Concentration Is Expressed Affects Dosing Errors

Epinephrine (adrenaline) is a drug that can be used to treat life-threatening allergies. The drug is stored in salt water and can be expressed as both a dose or mass concentration level (e.g. 1 mg per 1 mL of salt water) and a ratio (1 part drug for every 1000 parts of salt water).


This article appears in Annals of Internal Medicine.


A randomized, blinded, controlled study, designed to see whether labeling the drug as a dose or a ratio affected accuracy or speed in giving the drug, divided 28 doctors into two groups to handle a simulated severe allergic reaction.


The study found that all but two of the doctors in the group that used adrenaline in ampules with ratio labels gave more adrenaline (i.e. overdosed) and took longer to do so than the doctors in the group using ampules with dose labels (Article, p. 11).


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American College of Physicians