BACKGROUND: Our goal was to examine the following issues relevant to the use of liquid medications: (1) which liquid medication dosing devices are commonly owned and used; (2) the ability of potential patients to accurately measure liquids using 3 different dosing devices; (3) their ability to correctly interpret a variety of dosing instructions; and (4) their ability to correctly interpret a pediatric dosing chart.
METHODS: One hundred thirty volunteers from the waiting areas of 3 primary care clinics in the St. Paul, Minnesota, area were interviewed. Participants were shown 7 liquid dosing devices and were asked which they had in their homes and which they had ever used. The participants were tested and scored on their ability to measure liquid medicines and interpret dosing instructions accurately. The total performance score was determined, with a maximum obtainable score of 11.
RESULTS: A household teaspoon was the device most frequently used for measuring liquid medication. Women and participants with more education had higher total performance scores. Common errors included misinterpreting instructions, confusing teaspoons and tablespoons on a medicine cup, and misreading a dosage chart when weight and age were discordant.
CONCLUSIONS: Clinicians need to be aware that many people continue to use inaccurate devices for measuring liquid medication, such as household spoons. They should encourage the use of more accurate devices, particularly the oral dosing syringe. Clinicians should always consider the possibility of a medication dosing error when faced with an apparent treatment failure.
Nearly 25 years ago, the American Academy of Pediatrics (AAP) Committee on Drugs described the inaccuracies of administering liquid medication by household spoons.1 The Committee recommended that physicians advise their community pharmacies to stock appropriate liquid administration devices and insist on the use of such devices when prescribing liquid medications. The committee recommended the use of the oral dosing syringe, which was described as novel and innovative. Since then, a variety of liquid medication dosing devices have been developed and have become widely available, each of which ha sits advantages and disadvantages.2
Limited information is available about the current use of liquid medicine dosing devices in this country. In a 1975 study3 when the oral dosing syringe was still new, 75% of patients used a household teaspoon or kitchen measuring spoon when dosing liquid medication. In a 1989 study from Israel,4 80% of the children were given medications by a household teaspoon. The purpose of our study was to examine the following issues concerning the use of liquid medications: (1) which of the many liquid medication dosing devices are commonly owned and used by families; (2) the ability of potential patients to accurately measure liquids using 3 different dosing devices; (3) their ability to correctly interpret a variety of dosing instructions; and (4) their ability to correctly interpret a pediatric dosing chart.
Methods
Our study was approved by the institutional review board of Ramsey (now Regions) Hospital in St. Paul, Minnesota. In the summer of 1996, one of the investigators (F.S.M.) interviewed a convenience sample of people in the waiting areas of 3 clinics in the St. Paul, Minnesota, area: Ramsey Clinic Maplewood, a small private multispecialty clinic serving a predominately white middle-class suburban population; Ramsey Family Physicians, a residency clinic serving primarily a white lower-socioeconomic population; and West Side Clinic, a community clinic serving mostly Hmong and Hispanic patients. These clinics were chosen to obtain subjects with a variety of socioeconomic and ethnic backgrounds. The interview consisted of several parts. Participants were shown the following liquid dosing devices: cylindrical spoon, medicine cup, oral dosing syringe, oral dropper, andby dispenser. In addition, they were shown a household teaspoon and a measuring spoon ([Figure]). They were asked which of the dosing devices they had in their homes and which they had ever used for dispensing liquid medications. Demographic information was also obtained.
The participants were also tested and scored on their ability to measure liquid medicines and interpret dosing instructions accurately. A total performance score was determined by adding the scores from the following activities, with a maximum obtainable score of 11. The investigator observed the subjects measuring 3 doses of medicine using a cylindrical spoon, medicine cup, and an oral dosing syringe and noted the accuracy of the measurement. The subjects received a score of 0 or 1 if the measurement was done incorrectly or correctly, respectively, for each of the 3 devices. Then the subjects were asked to indicate on a chart what times they would take medicine if it was prescribed every 6 hours, 4 times daily, and 3 times daily. The subjects received a score of 0, 1, or 2 for each of these 3 charts. The score of 0 was given if both the number of doses and the timing were incorrect, a 1 if either the number of doses or the timing was correct, and a 2 if both were correct. Finally, subjects were shown a pediatric dosing chart that had dosing listed by both age and weight and contained a note that dosing by weight is more accurate. Subjects were asked to indicate the correct dose for 2 children. In one example the child’s age and weight matched on the chart, and in the other the age and weight were discordant. A score of 1 was given for each correct reading of the dosing chart.