We calculated descriptive statistics and frequency distributions for all variables. Chi-square analyses were used for categorical comparisons. Grouped t tests and analysis of variance techniques were used to assess the effect of categorical predictors and demographics on total score. Pearson correlations were calculated to assess relationships among continuous variables.
Results
Of the 130 participants, 105 were women. The participants had a mean age of 40 years, a mean education level of 12.5 years, and a mean of 1.1 children in the household. Sixty-eight percent of the subjects were white, 19% Hispanic, 11% African American, and 2% Asian. English was the second language for 13% of the participants.
The liquid dosing devices available in the participants’ homes and the devices they used are shown in the [Table]. The one most frequently used (73%) for measuring liquid medication was a household teaspoon.
Ninety-two percent of the participants measured the correct dose when using the oral dosing syringe. Only 85% of the participants measured the correct dose of 1 tablespoon when using a medicine cup. The most frequent error (70%) occurred when the participants mistakenly measured 1 teaspoon instead of 1 tablespoon. Although 92% of the subjects ultimately measured the correct dose using the cylindrical spoon, many subjects spilled the liquid and required several attempts before measuring the correct dose.
Eighty-nine percent of participants noted the correct number of doses and time between doses when asked to indicate the times that they would take a medicine if they were instructed to take it 4 times daily and 3 times daily. Only 38% of the participants correctly indicated this information when they were instructed to take a medication every 6 hours. Participants commonly misinterpreted this instruction as meaning every 6 hours while awake, and indicated 3 rather than 4 doses.
The pediatric dosing chart was correctly interpreted by 87% of the participants for both case scenarios. Twelve percent of those surveyed gave the incorrect dose when the age and weight of the child were discordant, choosing the dose based on the child’s age rather than weight.
The participants’ mean total performance score was 9.5. Women scored significantly better than men. (9.7 vs 8.7, P <.05). Total performance score was significantly correlated with the participants’ education level (Pearson correlation=0.177, P <.05), but not with age or the number of children in the household. Total performance score did not differ significantly by the participants’ native language or ethnic group.
Discussion
In 1975 the AAP Committee on Drugs denounced the use of household teaspoons for administering liquid medications.1 The volume of household teaspoons can range from 2 to 10 mL. Also, the same spoon when used by different persons may deliver from 3 to 7 mL. Therefore, even household measuring spoons are problematic. Participants in this study used a household teaspoon for measuring liquid medications more often than any other dosing device.
Oral dosing devices such as oral dosing syringes, oral droppers, cylindrical spoons, and medication cups are preferred over the traditional household teaspoon or measuring spoon, because they are more accurate. The advantages and disadvantages of the different devices have been described elsewhere.2 The cylindrical spoon has been described as having an increased potential for easy spillage before and during administration of medication.2 Participants in our study had problems with spillage with this device.
Study participants’ measurements were less accurate when using a measuring cup than when using a cylindrical spoon or oral dosing syringe, primarily because of confusion between the cup’s markings for tablespoons and teaspoons. A survey of poison control centers found 3 major causes of dosing errors using dispensing cups: (1) confusion of tablespoons for teaspoons; (2) the assumption that the entire cup was the unit of measure; and (3) the misinterpretation that 1 cupful was the recommended dose.5 After receiving reports of inappropriately marked plastic dosing cups, the Food and Drug Administration began a public education campaign in 1994 to increase health professional and consumer awareness of misdosing hazards with liquid medicines.6
The oral dosing syringe is felt to be the best device for delivery of liquid medication.2 Its advantages include accuracy, convenience, availability in various sizes, and relatively low expense. The syringe permits the user to direct the delivery of the medication to the back and side of the mouth of an infant or small child, thus minimizing spillage. It also reduces the risk of possible gagging and aspiration of medication. Only a third of this study’s participants had an oral dosing syringe in their home.
It is alarming that the majority of participants misinterpreted instructions to take a medicine every 6 hours, so that they would take only 3 rather than 4 doses of medicine in a day. This problem of misinterpreting dosing frequency appears to be relatively unrecognized, although it could be an important cause of apparent treatment failures. Studies of medication errors typically focus on mistakes that cause clinical symptoms. In a study of 1108 medication errors in pediatrics reported to poison control centers in France, none involved underdosage errors.7