Dosing directions and measuring devices included with top-selling pediatric over-the-counter liquid medications were highly inconsistent as of November 2009, when the Food and Drug Administration issued voluntary industry guidelines in response to numerous reports of unintentional overdoses among children, according to a descriptive study of 200 such medications.
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A study showed that 99% of 148 liquid medications with measuring devices had one or more inconsistencies between the markings on the device and the dosage directions.
The study, conducted to provide baseline data for assessing the degree and pace of industry conformity with the new guidelines, showed that 146 of 148 medications (98.6%) that included measuring devices had one or more inconsistencies between the dosing directions and the markings on the device, Dr. H. Shonna Yin of New York University and colleagues reported online in the Nov. 30 issue of JAMA.
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The inconsistencies included missing markings in 24% of the products, superfluous markings in 81% of the products, and inconsistencies between the product’s label and the measuring device in 89% of products.
Furthermore, 5.5% of the products used atypical units of measurement, such as cubic centimeters, drams, or fluid ounces; 71.5% used milliliters (although 97 products used a nonstandard abbreviation for milliliter); 77.5% used teaspoon units; and 18.5% used the tablespoon (JAMA 2010 Nov. 30[doi:10.1001/jama.2010.1797]).
Other potentially problematic findings included the lack of a leading zero in 12.5% of 40 products with a dose smaller than 1 presented in decimal format, the use of nonstandard fraction formats in 64.5% of 110 products that used fractions, and the lack of a statement that the measuring device should be used only with its associated product in 62% of the 148 medications that included a device.
The investigators evaluated 200 products representing 99% of the U.S. market of analgesic, cough/cold, allergy, and gastrointestinal OTC liquid products – including 58 private-label products – that contained dosing information for children under age 12 years. The medications were studied during the 52 weeks ending Oct. 30, 2009.
"Given the high prevalence of baseline inconsistencies, regulatory oversight may be helpful in accelerating adoption of the guidance recommendations," the investigators wrote, noting that several Institute of Medicine reports have identified variable and poor-quality drug labeling as a major cause of confusion among consumers – and therefore as a potential risk factor for unintentional misuse of products.
Indeed, many of the unintentional overdoses that prompted the FDA guidance in 2009 were attributed, at least in part, to products with inconsistent or confusing labels and measuring devices. The FDA recommendations state that:
• All OTC liquid medication products include a measuring device.
• Consistent abbreviations and units of measurement be used for a given product’s device.
• The devices bear only necessary markings and not hold significantly more medication than the largest prescribed dose.
• Abbreviations conform to standards and be defined.
• Decimals and fractions be used with care.
• Studies on accurate use of the medications by consumers be conducted.
More than half of all U.S. children are exposed to at least one medication in a given week – and more than half of those medications are OTC. Also at least one in three U.S. adults and at least one in four U.S. parents have limited health literacy and even worse numeracy. For these reasons, the findings support these recommendations and particularly underscore the need for standardized measuring devices with all nonprescription liquid products, consistency between dosing directions and markings on the measuring device, and standardization of measurement units, abbreviations, and numeric formats across products, Dr. Yin and associates said.
"Even frequently used terms like teaspoon and tablespoon may be misinterpreted," they wrote, noting that errors in understanding teaspoon vs. tablespoon have been found to contribute to threefold errors, and that the use of these terms endorses the use of kitchen spoons, which are known to be associated with measurement error.
More patient-centered research is needed to adequately address best practices under the FDA guidance, and to evaluate other aspects of product packaging and safe medication use, they said, concluding that since the FDA’s guidelines are voluntary, subsequent systematic product analyses may help monitor progress in terms of industry compliance – and assess whether additional regulatory oversight is needed to ensure safe and effective use of OTC medications.
This study was funded by a career development grant to Dr. Yin from the Robert Wood Johnson Physician Faculty Scholars Program. Dr. Yin also reported receiving funds from Pfizer and McKing Consulting Corp. Other authors on the study also said they received funding from Pfizer, McNeil Consumer Healthcare, Abbott, Johnson & Johnson, and/or McKing Consulting.