Recent findings serve as a reminder for clinicians to be sure patients administer liquid medicine in accurate measures when they are at home.
In a letter in Annals of Internal Medicine (2010;152:66-67), a pair of clinicians described their evaluation of spoon-dosing errors, after noting that spoon dosing is one of the three primary causes of dosing errors and pediatric poisonings.
Clinicians asked 195 patients to dose 5 mL of cold medicine into a teaspoon (5 mL, 2.7 x 4 cm) first, and then pour another 5 mL dose into a medium-sized tablespoon (15 mL, 4 x 6 cm) as well as a larger spoon (45 mL, 6 x 9 cm).
Participants underdosed by 8.4% when using the medium-sized spoon, and overdosed by 11.6% in the larger spoon. Nevertheless, the study subjects expressed above-average confidence that they had poured accurately.
“If a medicine’s efficacy is tied to its dose, it is more effective to encourage a patient to use a measuring cap, dosing spoon, measuring dropper, or a dosing syringe than to assume they can rely on their pouring experience and estimation abilities with tablespoons,” advise the investigators.
A February 2010 report in Archives of Pediatrics & Adolescent Medicine (164:181-186) showed that parents frequently made dosing errors when using cups compared with droppers, spoons, or syringes, and that strategies to reduce errors should address both accurate use of dosing instruments and health literacy.
Other researchers recommended that doses of antibiotics and other antimicrobial agents be calculated with the recipient’s body weight in mind to maximize the drugs’ potential effectiveness. Body size and composition can affect the way the body distributes, metabolizes, and clears an antimicrobial; this needs to be taken into account when prescribing antimicrobials to persons of non-average size (Lancet. 2010;375:248-251).