快樂小藥師 Im pharmacist nichts glücklich

Lori B. Hornsby; Heather P. Whitley; E. Kelly Hester; Melissa Thompson; Amy Donaldson

Posted: 08/20/2010; J Am Pharm Assoc. 2010;50(4):485-489. © 2010 American Pharmacists Association

Abstract and Introduction

Abstract

Objective: To assess patient knowledge regarding acetaminophen dosing, toxicity, and recognition of acetaminophen-containing products.
Design: Descriptive, nonexperimental, cross-sectional study.
Setting: Alabama, January 2007 to February 2008.
Patients: 284 patients at four outpatient medical facilities.
Intervention: 12-item investigator-administered questionnaire.
Main outcome measures: Degree of patient knowledge regarding acetaminophen safety, dosing recommendations, toxicity, alternative names and abbreviations, and products.
Results: Two-thirds of the 284 patients completing the survey reported current or recent use of pain, cold, or allergy medication. Of these, 25% reported knowing the active ingredient. Of patients, 46% and 13% knew that "acetaminophen" and "APAP," respectively, were synonymous with "Tylenol." Several patients (12%) believed that ingesting a harmful amount of acetaminophen was difficult or impossible. One-third of patients correctly identified the maximum daily dose, 10% reported a dose greater than 4 g, 25% were unsure of the dose, and 7% were unsure whether a maximum dose existed. One-half recognized liver damage as the primary toxicity. Results were similar between acetaminophen users and nonusers.
Conclusion: Deficiencies were found in patient knowledge regarding acetaminophen recognition, dosing, and potential for toxicity. The development of effective educational initiatives is warranted to ensure patient awareness and limit the potential for acetaminophen overdose.

Introduction

Acetaminophen, the most widely used analgesic in the United States, is consumed by more than 60 million Americans each week.^[1] When taken appropriately, acetaminophen is generally safe; however, hepatotoxicity may occur with ingestion of doses above the recommended 4 g or in patients with risk factors for hepatotoxicity.^[2,3] Acetaminophen is the primary single agent responsible for poisonings and is now reported as the leading cause of acute liver failure (ALF) in the United States.^[4–7] Although previously associated with suicide attempts primarily, hepatotoxicity secondary to unintentional overdose has recently been reported to account for 30% to 57% of all acetaminophen-induced ALF cases.^[5–8] 

Unintentional toxicity has been estimated to account for more than 13,000 emergency department visits, 2,000 hospitalizations, 1,000 to 2,000 cases of ALF, and 100 deaths annually.^[9] Factors thought to contribute include acetaminophen's widespread use and availability in varying preparations (both prescription and over the counter [OTC]), lack of patient awareness about active ingredients and recognition of acetaminophen products, and misconceptions regarding the dangers of OTC medications leading to misuse.^[9] 

Objective

To better assess patient understanding of acetaminophenrelated issues, we undertook a survey to assess patient knowledge regarding acetaminophen dosing, toxicity, and recognition of acetaminophen-containing products.

Methods

A 12-question survey was developed by the investigators to assess patient knowledge regarding acetaminophen safety, dosing recommendations, toxicity, alternative names and abbreviations, and products containing acetaminophen (Appendix 1 in electronic version of this article, available online at www.japha.org). Patients who were 19 years of age or older attending four participating outpatient facilities in Alabama were eligible for inclusion. Patients were chosen for participation by convenience sampling based on investigator availability from January 2007 to February 2008. Individuals who were unable to communicate or cognitively impaired were excluded. All surveys were administered by pharmacists or student pharmacists, who read each question to patients and recorded their answers. Students were trained on proper phrasing of questions and answer choices before participating.

Patients were questioned regarding current and/or recent use of pain, cold, or allergy medications (both prescription and OTC) and knowledge of active ingredient. They were asked to identify alternative names or abbreviations for Tylenol from a list containing both acetaminophen and APAP. Patients were shown a graphic of three prescription labels, all of which contained the abbreviation APAP, and asked to identify whether each label was for a product containing Tylenol. Knowledge of acetaminophen-related toxicity was assessed in a series of multiple-choice questions related to the overall potential for harm, recommended daily dose, and specific adverse effects. The brand name Tylenol was used in questioning to eliminate biasing results. When appropriate, an answer choice of "I don't know" or "unsure" was included to best assess actual knowledge. The study was approved by the Auburn University Institutional Review Board. Patients were provided with information letters after consenting to participate. Results were analyzed using descriptive statistics.

Results

Participant Demographics, Medication Use, and knowledge of Active Ingredient

Demographics for the 284 participants are shown in Table 1. Of the patients, 59% (n = 167) reported current use of a prescription or nonprescription medication for pain, cold, or allergy symptoms. Of the remaining 117 patients, 41% (n = 48) reported use within the preceding 30 days. Only 25% (n = 53) of those reporting current or recent use stated that they were knowledgeable of the active ingredient.

Table 1. Demographics of participants in survey assessing patient knowledge of acetaminophen

Acetaminophen Recognition

Only 46% (n = 131) of patients knew that acetaminophen was synonymous with Tylenol. Of patients, 16% (n = 42) reported that acetaminophen and Tylenol were different products. The remaining patients were either unsure (35%) or did not answer (2.8%). Only 13% (n = 38) agreed that APAP was an abbreviation for Tylenol; 25% (n = 71) disagreed, and the majority (60%, n = 170) were unsure. Collectively, only 11% (n = 30) identified both acetaminophen and APAP as alternative names for Tylenol. Table 2 shows the proportions of patients correctly identifying "other names for Tylenol." The majority of patients did not identify acetaminophen- containing prescription labels as products containing Tylenol (Table 3). Only 13% (n = 36) correctly identified all three labels.

Table 2. Participant knowledge of "other names or abbreviations for Tylenol"^a 

^aPatients were asked the following question: Are any of the following other names or abbreviations for Tylenol?

Table 3. Participant recognition of medication labels containing Tylenol

^a11 patients reported inability to answer as a result of visual impairment.
^b13 patients reported inability to answer as a result of visual impairment.

Acetaminophen Users

Of the 284 participants, 37% (n = 104) were determined to be taking an acetaminophen-containing product. Of these, 26% (n = 27) reported knowledge of the active ingredient, 58% (n = 60) reported not knowing, and 16% (n = 17) did not answer. When questioning those who were not aware of the active ingredient regarding the possibility of "Tylenol" as a component, 57% (n = 34) indicated that Tylenol could be an ingredient, 25% (n = 15) did not believe Tylenol was a component, and the remaining 18% (n = 11) did not answer. Acetaminophen users responded similarly to total participants regarding acetaminophen and APAP being alternative names and abbreviations (Table 2) and in their ability to recognize acetaminophen-containing prescription labels (Table 3).

Table 2. Participant knowledge of "other names or abbreviations for Tylenol"^a 

^aPatients were asked the following question: Are any of the following other names or abbreviations for Tylenol?

Table 3. Participant recognition of medication labels containing Tylenol

^a11 patients reported inability to answer as a result of visual impairment.
^b13 patients reported inability to answer as a result of visual impairment.

Overdose Potential

Although most participants (84%, n = 238) were aware of the potential to consume a toxic amount of acetaminophen, 5% (n = 14) reported that taking a quantity sufficient to cause harm was not possible; the remainder believed that it would be difficult to take a harmful amount (7%, n = 21) or did not respond (4%, n = 11). Of those who believed that taking a harmful amount was possible (n = 270), 33% (n = 84) knew the recommended maximum daily dose (4 g), 23% (n = 62) selected amounts less than 4 g as the maximum daily dose, 10% (n = 27) selected amounts greater than 4 g as the maximum daily dose, 25% (n = 68) acknowledged that a maximum daily dose existed but were unsure of the quantity, 7% (n = 18) were unsure whether a maximum daily dose existed, and 3% (n = 7) did not answer. Of these patients acknowledging the potential for toxicity, 50% (n = 134) recognized liver damage as the primary concern. The remaining participants chose other various toxicities.

Discussion

Data from the FDA Adverse Event Reporting System and several trials suggested that a substantial number of patients with unintentional acetaminophen-induced ALF had ingest- ed multiple acetaminophen products.^[6–8] Explanations were mostly related to lack of knowledge concerning medication contents and potential dangers of acetaminophen misuse.^[7] These issues were demonstrated in our survey. Less than one-half of all patients were aware that acetaminophen was synonymous with Tylenol and fewer were familiar with the abbreviation APAP. Also of note, similar findings were observed in patients known to be taking acetaminophen. Onefourth of acetaminophen users did not believe that they were using a Tylenol-containing product. The inability of patients, specifically those ingesting acetaminophen, to accurately identify alternative names and abbreviations is alarming.

Two previous studies reported similar disconcerting results.^[10,11] Chen et al.^[10] surveyed 103 patients and found that more patients identified nonacetaminophen products as acetaminophen products than accurately identified acetaminophen- containing products as such. A high percent of 104 patients surveyed by Stumpf et al.^[11] correctly identified "Tylenol" as acetaminophen; however, the investigators included the statement "Tylenol or any other medication containing acetaminophen" in their survey, which may have biased the results. Despite that statement, only 50% identified Tylenol PM as containing acetaminophen. Fewer than 15% were aware that Vicodin, Darvocet, Tylox, Percocet, and Lorcet contained acetaminophen. More patients believed acetaminophen was the active ingredient in Motrin than in actual acetaminophen-containing products.

During a 2002 hearing, the FDA Nonprescription Drugs Advisory Committee recommended that all OTC acetaminophen- containing products display the statement "this product contains acetaminophen" on the package label and clearly identify liver failure as the major toxicity.^[9] These recommendations were later implemented in 2006.^[2] In 2004, FDA contacted state boards of pharmacy asking for mandates requiring acetaminophen-containing prescription products to clearly state "acetaminophen" on the label rather than using abbreviations.^[12,13] In a later report, FDA stated that as of February 2008, labeling requirements for prescription products had not been mandated by any state board.^[13]

Although warranted, labeling changes alone will likely fall short of an effective solution. A survey of more than 4,000 adults by the National Consumers League found that most patients read very little labeling information before taking OTC pain medication, including upon first use.^[14] Only 30% reported reading dosing information and 16% read information pertaining to adverse effects—;practices most likely stemming from misconceptions related to the dangers of OTC products. The survey also reported that 50% of patients were "not very concerned" (25%) or "not concerned at all" (25%) about potential adverse effects of OTC pain products . In the current work, a small but discouraging percent of patients appeared to underestimate the dangers of acetaminophen by reporting impossibility (5%) or difficulty (7%) in consuming a harmful amount. Interestingly, in the National Consumers League survey, after being educated about potential dangers of various OTC pain medications, greater than 75% of participants reported being concerned about adverse effects.^[14]

Knowledge of maximum doses is important because most unintentional poisonings occur in patients ingesting amounts over the daily recommended dose.^[6,8] In the survey of Chen et al.^[10]described above, 18% of patients overestimated the maximum dose of acetaminophen, with 6% reporting doses more than 10 g as safe. Surprisingly, Stumpf et al.^[11] reported that 70% of patients underestimated the maximum daily dose, although 28% were unsure. In the current study, only one-third of patients chose the appropriate maximum daily dose, 10% overestimated the maximum daily dose, and 25% admitted not knowing the maximum daily dose. Regardless of knowledge concerning recommended doses, patients may still intentionally ingest more than the recommended dose without intentions of self-harm.^[14] Reasons sighted in the National Consumers League survey included attempts to achieve pain relief more quickly, believing larger doses were warranted based on pain severity, and attempts to improve pain unrelieved initially by recommended doses.^[14] These practices demonstrate the overall lack of understanding and awareness leading to dangerous medication use practices.

Our findings strongly support efforts by FDA to improve the safe use of acetaminophen. In June 2009, an FDA advisory committee acknowledged that a 2004 education campaign was hindered by budgetary constraints and resistance from venues selling acetaminophen products. Other than intensifying and sustaining education efforts, potential actions discussed included lowering the recommended maximum dose, expanding labeling changes to prescription products, packaging products in units of use, restricting OTC package sizes, limiting OTC dosage formulations, and potentially eliminating all combination products.^[15] Although these suggestions have merits, we believe that they do not replace education initiatives.

Health care providers must be aware of unintentional acetaminophen overdose, question patients about prescription and OTC use, and discuss the hazards of duplicate therapy. Pharmacists should counsel all patients when dispensing acetaminophen-containing products to ensure awareness of active ingredients and the potential for hepatotoxicity. Patients should be encouraged to discuss the use of all OTC medications with both their physician and pharmacist, follow directions for use, and, most importantly, verify the active ingredient in OTC products.

Limitations

This study had several limitations. Surveys were limited to one state; therefore, extrapolating the results may not be possible. Patients were chosen by convenience sampling, which is subject to bias; however, we do not feel that this was a major limitation because of the nature of our survey. The survey was not validated and did not involve a predetermined analytic plan. A small percentage of questions were not answered for reasons that were unclear. Although we felt this most likely signified a response of "unsure" or "unknown," we did not feel that making these assumptions was appropriate.

Conclusion

The current investigation demonstrates the deficiencies in patient knowledge related to acetaminophen recognition, dosing recommendations, and potential for toxicity. The development of effective initiatives to educate both the public and health care providers is warranted to ensure patient awareness and limit the potential for acetaminophen overdose. Pharmacists are in a position to lead these medication safety efforts by ensuring that all patients receiving acetaminophen products are counseled appropriately.

References

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