Accuracy of Oral Liquid Measuring Devices: Comparison of Dosing Cup and Oral Dosing Syringe

Abstract

Background: Previous studies have found that teaspoons are commonly used to administer liquid medications to children. The capacity of household teaspoons ranges from 1.5 mL to 9 mL, potentially leading to errors in dosing. There are few studies evaluating alternative measuring devices. Objective: To assess adult consumers’ previous experience with measuring devices for oral liquids, compare the accuracy of an oral syringe with that of a dosing cup, and determine consumer perceptions of accuracy and ease of use of an oral syringe and a dosing cup. Methods: Individuals at least 18 years of age were shown a picture of 5 commonly used measurement devices and asked their perceptions of and experience with the devices. They were then asked to measure a 5 mL (1 teaspoon) dose of Tylenol (acetaminophen) suspension, using the EZY Dose oral syringe and the dosing cup provided by the manufacturer. An acceptable dose was defined as 5.0 ± 0.5 mL. Following the measurement, participants completed a 5 item survey that assessed their perceptions of the accuracy and ease of use of the syringe and dosing cup. Results: A total of 96 subjects completed the study. Participants more commonly reported use of droppers (68%), dosing cups (67%), and teaspoons (62%) versus cylindrical spoons (49%) or oral syringes (49%) for measuring oral liquids. Sixty-four (66.7%) subjects measured an acceptable dose using the syringe versus 14 subjects (14.6%) using the cup (p < 0.001). The mean volumes ± SD measured with the syringe and cup were 4.5 ± 0.7 mL and 6.3 ± 0.7 mL, respectively (p < 0.001). After using both devices, the majority of subjects believed that the syringe (80%) and cup (71%) would measure an accurate dose. Most (87%) participants perceived that the cup was easy to use; 63% believed that the syringe was easy to use. Conclusions: Droppers and dosing cups were the most commonly used devices in the home for measuring liquid medications. Subjects were more likely to measure an acceptable dose with an oral syringe when compared with a dosing cup. However, a large proportion of study participants were unable to measure an accurate dose with either device. Community pharmacists should educate caregivers on the selection and proper use of measuring devices to improve the accuracy of medication administration in the home.