Paracetamol-associated knowledge, attitudes and practices of the New Zealand public: an online survey

Introduction

Paracetamol is the most widely used prescription and over-the-counter drug in the world.¹ It is the first-line treatment for acute and chronic pain conditions and represents the first step on the World Health Organization (WHO) pain management ladder.² Although generally perceived as safe,³ paracetamol represents a dose-related toxin,⁴ with a higher potential for clinically significant toxicity than other common non-opioid analgesics, such as ibuprofen and aspirin.⁵ Paracetamol toxicity is possible in a range of situations, including a single acute over-administration, repeated supra-therapeutic doses, or therapeutic administration in hepatotoxicity-susceptible individuals.⁶ Availability of the established paracetamol antidote, N-acetylcysteine, in most developed countries can prevent mortality and morbidity; however, delays in presentation and treatment can result in significant hepatotoxicity, and paracetamol is a leading preventable cause of acute liver failure.⁷

In Aotearoa New Zealand (NZ), paracetamol ingestion is the most frequent reason for calls about therapeutic agent exposures to the poison information centre.⁸ It is relatively cheap and readily available at both pharmacy and non-pharmacy outlets. Pharmacies can dispense up to 300 tablets of paracetamol 500 mg with a prescription⁹ (13 May 2024) and sell up to 50 g of immediate-release and 64 g of modified-release paracetamol without a prescription. Non-pharmacy outlets, including supermarkets, can sell a maximum of 10 g of paracetamol per package without a formal limit to how many packets can be purchased.¹⁰ Although evidence suggests that regulation of paracetamol products reduces harm, other factors related to paracetamol use, such as prescriber behaviour and public knowledge and attitudes, are also important.^11–13 There is international evidence that the general public tends to have inadequate knowledge of paracetamol and its safe usage.^14,15

Knowledge, attitudes and practices (KAP) surveys are designed to uncover information about what is known, believed, and done in the context of a specific topic and are undertaken in a representative sample.¹⁶ The KAP approach can reveal gaps in knowledge to enhance the effectiveness of public health activities while identifying barriers to behaviour change.¹⁷ The NZ public’s paracetamol-associated knowledge, attitudes and beliefs have not been explicitly investigated. This study sought to identify and describe the paracetamol-associated knowledge, attitudes and practices of the NZ public and then examine the relationship between knowledge and patterns of paracetamol misuse.

Methods

Results

A total of 2238 respondents initiated the online study, of which 285 were removed after quality checking because they either did not meet the inclusion criteria (n = 217) or did not complete the survey (n = 68). Overall, 1723 NZ adults responded to the survey (77% of those who initiated responses). The characteristics of respondents are presented in Table 1. The sample was balanced for gender and age. The proportion of Māori included in the survey represented the Māori population in NZ; however, Pacific respondents were slightly under-represented compared to NZ’s Pacific population.

Recommended guidelines for paracetamol use

The proportions of respondents reporting exceeding the recommended paracetamol dosage in 24 h, taking more than two tablets in a single dose, and not waiting 4 h between doses are illustrated in Fig. 1.

Fig. 1.

Proportion of respondents exceeding recommended dosing guidelines for paracetamol.

Discussion

This is the first study to investigate the knowledge, attitudes and practices of adults living in NZ regarding paracetamol use and prescribing. In this large sample, which is generally well representative of the NZ population, we found that regular paracetamol consumption in NZ is high, with over half of respondents taking the drug at least a few times per month. Further, most respondents report always keeping a stock of paracetamol at home, with supermarket purchases and doctor prescriptions representing the two most common sources of paracetamol. The practice of asking general practitioners for a prescription of paracetamol, even when that is not the reason for the patient visit, and sharing prescribed paracetamol with family and friends, is also common in this population. Overall, there is a perception that paracetamol is a safe drug that is very easy to obtain, with a large proportion of respondents agreeing that it is too easy to get large doses of paracetamol and that restrictions on paracetamol should be increased, including how much you can purchase at one time. Finally, we found that despite almost all respondents reporting knowing how to take paracetamol safely, a substantial proportion of the NZ adult population exceeds paracetamol dosing guidelines.

This study had several strengths, including the relatively large sample size and inclusion of a sample generally representative of the NZ population, according to age, sex and ethnicity. Further, we were able to build on previous NZ research by incorporating a more diverse sample.¹⁰ To the best of our knowledge, this is also the first study in NZ to investigate inappropriate paracetamol use and specific knowledge, attitudes and practices related to paracetamol in the general public.

Several limitations must be acknowledged. The panel member participants may not be representative of the general population, as they may be more likely to be computer literate and have access to the internet. We did not collect data on deprivation or rurality of the sample, and these data would likely have influenced responses. Further, some individuals may have declined to participate because of a lack of interest or time constraints, which may have further influenced the characteristics of the sample. Although using an online panel enabled us to reach many participants throughout NZ, a potential limitation of this approach is selection bias. One approach to addressing this issue would be combining different recruitment strategies to ensure a more representative sample. Another potential limitation is measurement bias.

The accuracy and validity of the responses obtained through the online panel may have been affected by factors such as the clarity and wording of the questions, the response options provided, and the order in which questions were presented. One of the questions about the misuse of paracetamol was confusing for some respondents, with some reporting that they had misread the question but could not go back to change it. Further, there was also potential for reporting bias, where, for example, participants may have indicated that they had read the leaflet or pack to appear to be responsible users. Finally, although we investigated participant perceptions of interactions with prescribers about paracetamol, it is necessary to highlight that these were perceptions of the NZ public and may not represent actual practice.

This study is a relatively large survey of community knowledge, attitudes and practices relating to paracetamol. Most households in NZ are likely to have stocks of paracetamol (83.5%), most of which were sourced from a pharmacy. These findings concur with a smaller, in-person, cross-sectional study conducted in two NZ cities that found that 86.6% of surveyed households (n = 201) had at least one paracetamol product.¹⁰ However, although this previous study reported the primary source of household paracetamol was a doctor’s prescription, our research found that doctors’ prescriptions and supermarkets were equally common sources of paracetamol. This difference may be caused by how data was collected, with the 2019 study involving research assistants directly approaching households and asking participants to physically go into their houses and bring out all their paracetamol-containing drugs. Further, the difference between studies may have resulted from the different sampling frames, with the current study being more representative of the general population. At the same time, the 2019 study was only conducted in two urban areas, which may impact where people source their paracetamol.¹⁰ Alternatively, the 2019 study included representative proportions of respondents according to neighbourhood deprivation. Unfortunately, we did not collect these data in the current study and cannot say whether our sample was representative according to deprivation.

Paracetamol-related knowledge was mixed. Although adequate knowledge was demonstrated for the appropriate indication of paracetamol, we identified knowledge gaps around dosing guidelines and identifying formulations containing paracetamol and other drugs. Similar patterns of paracetamol-related knowledge have been demonstrated internationally. A recent survey of the general public in Thailand (n = 1982) found that although over 90% of respondents correctly answered questions regarding the indication of paracetamol for fever, only 22% knew the recommended daily dose.²⁰ Further, another study, which asked patients in the emergency department triage of a London hospital (n = 910) to identify commonly used over-the-counter and prescription analgesics and cough and cold remedies containing paracetamol, found that knowledge was insufficient for ensuring the safe use of paracetamol.²¹ A significant gap in knowledge regarding paracetamol-containing formulations has also been demonstrated in the United States where, in a convenience sample of 1009 participants recruited at an emergency department, 49% did not know that Tylenol^® contained paracetamol.²²

An important finding of our study was the high level of inappropriate paracetamol use. Almost one-third of participants reported taking more than two 500 mg of paracetamol in a single dose, exceeding the maximum of 1 g per dose guideline. Further, over 1 in 10 respondents reported exceeding the recommended daily intake of paracetamol, which aligns with findings from overseas.^20,23,24 Not surprisingly, respondents who reported not knowing how to take paracetamol safely or were unsure about how to take paracetamol safely were more likely to have exceeded paracetamol treatment guidelines. Interestingly, we did not find a difference in misuse of paracetamol between respondents who had read the guidelines, either outside the box or on the included leaflet, and those who had not. These findings suggest that although knowledge is essential for adhering to paracetamol recommendations, this knowledge may not necessarily result from reading the guidelines in or on the box. Future research will need to investigate how the NZ public obtain their understanding of the safe use of paracetamol, particularly given the reported low rates of perceived advice provided by doctors and pharmacists.

Concerning paracetamol-related attitudes, we found that despite most participants saying that paracetamol is a safe drug, over half wanted restrictions on how much paracetamol can be bought at once, although less than one-third reported that there should be restrictions on where to buy paracetamol. Further, just under half reported that it is too easy to get large doses of paracetamol in NZ, whereas three-quarters said getting a prescription for paracetamol is easy, indicating that a significant proportion of participants did not perceive barriers to obtaining a prescription. The appropriateness of prescribing was not investigated here, and future research should look into this. Although these findings are somewhat mixed, they may have important implications moving forward, given NZ's current regulatory environment around the supply of paracetamol.

Conclusion

This study highlights the relatively high rates of unintentional misuse of paracetamol and significant knowledge gaps, specifically identifying paracetamol-containing formulations and safe dosing. At the same time, we found moderate public support for introducing policies around the supply and sale of paracetamol.