Knowledge of dosing directions among current users of acetaminophen-containing medications.

OBJECTIVES: Users should know the active ingredients and dosing directions to optimize the safe use of acetaminophen-containing medications. The aim of this work was to examine knowledge of acetaminophen-containing medication directions among current users. DESIGN, SETTING, AND PARTICIPANTS: An Internet panel diary study (2012-2016) of 1-week usage of acetaminophen medications (over-the-counter [OTC] and prescription), recorded daily; 9629 participants. Users were asked about ingredients of medications taken; specific dosing instructions were asked for each OTC medication taken. Subjects were considered to be correct only if an accurate response was provided for all of the medications they used. OUTCOME MEASURES: Analyses examined prevalence of several aspects of knowledge and their relation to the corresponding deviations from directions. Knowledge that acetaminophen was an ingredient was compared between medication types. RESULTS: Two-thirds of 5161 participants who used only 1 acetaminophen medication knew the ingredient; the proportion was almost halved in 4468 users of 2 or more. Ingredient knowledge was highest for single-ingredient medications (74%); for combination medications it ranged from 39% (cough or cold) to 61% (sleep or other non-pain). About one-third knew the prohibition against concomitant use of multiple acetaminophen medications; 85% knew the maximum one-time OTC dose, but only 47% knew the minimum interval between doses. Correct knowledge was inversely associated with violating the relevant label directions; in particular, knowing the one-time dose decreased the odds of taking too much at one time fivefold. Knowing both the ingredient and the concomitant use prohibition decreased the odds of concomitant use by 50%. CONCLUSIONS: Knowledge of directions for safe use of acetaminophen-containing medications is poor, and its deficiency is associated with corresponding deviations from label instructions. This study demonstrates a need for education about safe use of acetaminophen-containing medications, particularly for combination products.

Exceeding the daily dosing limit of nonsteroidal anti-inflammatory drugs among ibuprofen users.

PURPOSE: Nonsteroidal anti-inflammatory drugs (NSAIDs) are effective and very commonly used, but also have side effects. We determined prevalence of NSAID dosing exceeding the daily limit (EDL) and identified related user characteristics and dosing patterns among current ibuprofen users. METHODS: Online 1-week diary study of 1326 ibuprofen users. NSAIDs were identified by list-based prompting; respondents were not required to know their medications were NSAIDs. Details of hourly use were recorded by respondents daily. Deviations from dosing directions were programmatically determined afterwards. An exit survey obtained information on demographics, medical history, physical and mental health status, attitudes regarding label reading and dosing behavior, and knowledge of product label instructions. RESULTS: Most diary users (90%) took over-the-counter ibuprofen during the week; 37% also took non-ibuprofen NSAIDs. Most did not recognize all products taken as NSAIDs. EDL occurred among 11% of users for ibuprofen, 4% of users for other NSAIDs, and on 9.1% of NSAID usage days. EDL was associated with deviations from detailed dosing directions, particularly exceeding the 1-time dose, which occurred more often with medications with 1-pill doses. Personal characteristics associated with EDL included male sex, ongoing pain, poor physical function, daily smoking, having the attitudes of "choosing my own dose" and not starting with the lowest dose, and poor knowledge of the recommended 1-time and 24-hour doses. CONCLUSIONS: The prevalence of EDL among NSAID users is nontrivial, and it is associated with potentially modifiable factors. Educating consumers about NSAIDs and their dosing directions could reduce excess dosing.

Relation of Health Literacy to Exceeding the Labeled Maximum Daily Dose of Acetaminophen.

INTRODUCTION: Acetaminophen is a commonly used analgesic/antipyretic; overdoses can lead to liver damage. Little is known about the relationship of health literacy to exceeding the recommended maximum daily dose (4 g). METHODS: Subjects were recruited at 23 U.S. malls in 2011. Health literacy was measured by Rapid Estimate of Adult Literacy in Medicine (REALM), classified as very low (VLL, score <45); low (LL, 45-60); or adequate (AL, >60). Participants completed a 7-day acetaminophen use diary by daily telephone interview; an exit interview covered demographics, physical/mental health, medical history, medication label reading, and medication-taking knowledge/attitudes. Acetaminophen products were identified from a comprehensive list; subjects were not required to know their medications contained acetaminophen. Seven hundred fifty-six subjects aged ≥18 years had taken acetaminophen in the past 30 days and completed 7 diary days with ≥1 day of acetaminophen use, plus the exit survey. Analysis was conducted in 2012-2014. RESULTS: VLL were more likely than AL individuals to exceed 4 g on ≥1 day (OR [95% CI]=3.8 [1.5, 9.6]; 4.0 [1.3, 12] after controlling for five REALM score-related factors). On usage days, VLL individuals were also more likely to exceed 4 g (3.3 [1.1, 10], by generalized estimating equations; 2.4 [0.9, 6.6], direct effect after accounting for mediation by other deviations from label recommendations). CONCLUSIONS: VLL individuals exceed the recommended maximum acetaminophen dose more often than AL individuals. Other identified characteristics related to health literacy do not explain this, but it is partly mediated by increased frequency of other label deviations.

Prevalence and correlates of exceeding the labeled maximum dose of acetaminophen among adults in a U.S.-based internet survey.

PURPOSE: Acetaminophen is a commonly used analgesic; excessive doses can lead to liver damage. We sought to determine the proportion of acetaminophen users exceeding the recommended maximum daily dose of 4 g and identify correlates of such behavior. METHODS: U.S. adults were recruited from an internet panel in summer 2010, oversampling past 30-day acetaminophen users. Among 47 738 starting the study, 5649 completed all phases; individuals with low education were underrepresented. Subjects completed a 7-day daily diary online, reporting intake of acetaminophen products selected from a comprehensive list; total daily dose was computed from product names. An exit survey elicited: attitudes/knowledge related to product ingredients, label reading, dosing behavior; demographics, medical history, general physical, and mental health status. Unconditional logistic regression identified variables independently associated with use exceeding 4 g. RESULTS: Among 3618 acetaminophen users, 163 took >4 g on ≥1 day (4.5%); the median dose was 5.5 g; 26 took >8 g (0.7%). >4-g users were characterized by chronic pain, poor physical status, and heavy use of medical care. Knowledge of ingredients and recommended OTC doses for all products taken was inversely associated with >4-g use (multivariable odds ratios [ORs] = 0.5-0.6), as was the attitude to start with the lowest dose (OR = 0.6). The attitude that users could choose their own dose was positively associated (OR = 1.3). CONCLUSIONS: The results estimate the proportion of acetaminophen users exceeding 4 g in a group of U.S. adults, identify potentially modifiable attitudes and knowledge associated with such use, and characterize subpopulations at higher risk.