High Levels of Variability and Inconsistencies in Dosing Directions and Measuring Devices in Pediatric OTC Medications

Results of a descriptive study of the top-selling 200 pediatric oral liquid over-the-counter (OTC) medications on the market during 52 weeks ending October 30, 2009, found high levels of variability and inconsistency in dosing directions and measuring devices [JAMA. 2010;304(23):2595-2602].

These results represent findings of OTC medications on the market prior to newly released voluntary guidelines by the US Food and Drug Administration (FDA) in November 2009 that provided recommended ways for industry groups that manufacture OTC liquid medications, particularly to children, to improve consistency and clarity of OTC instructions to consumers.

Conducted to determine the prevalence of inconsistent dosing directions and measuring devices among the most popular pediatric OTC medications at the time of the release of the FDA guidelines, the “study provides baseline data for assessing the degree and pace of industry conformity with the FDA’s voluntary guidelines,” according to the investigators.

Using data from IMS Health, a provider of market intelligence to pharmaceutical and healthcare industries, the study identified the top-selling nonprescription medications categorized as analgesic, cough/ cold, allergy, or gastrointestinal products. To be included in the study, the medications had to be a liquid for oral administration and had to include dosing directions for a child <12 years of age.

Of the 340 eligible OTC products from the IMS Health database, 200 products with the highest US market share based on number sold (representing 99% of US market share) were included in the analysis.

Analysis of each of the 200 products was done independently by 2 investigators based on the criteria used to establish the FDA recommendations. These criteria included assessing the presence and type of measuring device, the within-product inconsistency between labeled dosing directions and measuring device, across-product variability, and consumer guidance on appropriate use.

The study found highly variable and inconsistent dosing instructions. A total of 11 (5.5%) of the products used nonstandard units of measurement, such as dram and cubic centimeter. The most frequently used units of measurement were milliliter in 143 products (71.5%) and teaspoon in 155 products (77.5%). In 37 products (18.5%), tablespoon was used. Among the products that used measurements in milliliters, teaspoons, and tablespoons, most included at least 1 nonstandard abbreviation. For example, 97 products used a nonstandard abbreviation for milliliter (not mL). In addition, abbreviations used in products were often not defined. In the study, 163 products did not define at least 1 abbreviation.

The study also found that of the 200 products, 148 (74.0%) included measuring devices. Products for gastrointestinal conditions were the least likely to include a measuring device. Of the 148 products with measuring devices, 146 (98.6%) had inconsistencies between the medication’s dosing directions and markings on the device. Missed markings were found in 36 products (24.3%) and superfluous markings in 120 products (81.1%).

Based on these findings, the investigators highlight 3 critical areas that need to be addressed based on the FDA criteria: (1) inclusion of a standardized measuring device, (2) consistency within each product between the labeled dosing directions and markings on the associated measuring device, and (3) standardization of units of measurements, abbreviations, and numeric formats across all products.

Limitations of the study, according to the investigators, include a lack of direct assessment of consumer understanding and use of the products and a lack of examination of other critical aspects of safe medication use (weight- vs age-based dosing, maximum dosing, understanding of active ingredients of products).

According to the investigators, future systematic product analyses may help monitor the progress made by industry to adopt the FDA recommendations, including “assessing whether additional regulatory oversight may be needed to ensure practices that best support safe and effective use of OTC medications.”