Introduction

Dental pain is a commonly reported oral health problem which can cause detrimental impact on normal physical health and psychological well-being [1–3]. In dental pain management, pain alleviation is of the utmost importance and analgesics including opioid and non-opioid analgesics are commonly prescribed to alleviate this pain [4–7]. Non-opioid analgesics including paracetamol and ibuprofen can be obtained without prescription in most of the countries including Malaysia. Thus, patients experiencing dental pain tend to self-medicate with these analgesics in hopes of avoiding dental treatment [1,8].

According to the World Health Organisation, self-medication is defined as the use of medicine for self-diagnosed disorders or the intermittent or continued use of a prescribed medicine for recurring or chronic disorders [9]. Currently, self-medication among patients with dental pain is a common practice driven by various underlying factors. Surprisingly, it was found that beliefs about medicines contributed to the practice of self-medication [1,8,10–13].

Belief is the mental acceptance of the actuality of an idea [14]. According to self-regulatory theory, the decision on choosing a coping action for an illness is influenced by beliefs about the potential cure of that illness [15]. Beliefs about medicines are commonly evaluated by Beliefs about Medicines Questionnaire (BMQ) [15]. BMQ can be used as the predictor of medication adherence. However, a recent study conducted in Sweden reported that individuals who used Over-The-Counter medicines had stronger beliefs about the benefits of medicines and weaker beliefs in viewing medicines as harmful and overused [16–20]. Thus, it was postulated that beliefs about medicines were related to self-medication as these beliefs might influence patient’s decision on taking a certain medicine for self-diagnosed disorders.

To the best of our knowledge, there is no information on the relationship between beliefs about medicines and self-medication with analgesics in patients with dental pain. As analgesic is the most frequently used medicine for self-medication in dental pain management and potential adverse consequences including renal failure can occur due to prolonged use of analgesics [1,8,10–12], the main objective of this study was to evaluate the relationship between beliefs about medicines and self-medication with analgesics in dental pain management.

Methods

Results

Sociodemographic characteristics

A total of 153 patients participated in this study. Participant’s sociodemographic and dental pain intensity are presented in Table 1. The mean age of participants was 43.4 ± 15.2 (range: 19–75). Over half of the participants were female (58.8%) and approximately three-quarter of them were Chinese (71.9%). The mean dental pain intensity was 2.7 ± 1.2 (range: 1–5).

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Table 1. Sociodemographic of participants (n = 153).

https://doi.org/10.1371/journal.pone.0201776.t001

Dental pain-related characteristics

Participant's dental pain-related characteristics are reported in Table 2. Most participants (79.1%) experienced pain originating from their tooth/teeth in the past one month. Majority of the participants had mild (57%) and episodic (77%) dental pain.

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Table 2. Frequency distribution of the modified dental pain questionnaire (n = 153).

https://doi.org/10.1371/journal.pone.0201776.t002

Beliefs about medicines

BMQ-Specific and BMQ-General subscales demonstrated good and acceptable internal consistency, respectively (Specific-Necessity, α = 0.781; Specific-Concern, α = 0.770; General-Harm, α = 0.620; General-Overuse, α = 0.520). The mean score of each item of BMQ was reported in Table 3. Meanwhile, the mean total score of Specific-Necessity, Specific-Concern, General-Harm and General-Overuse were 10.9 ± 4.5 (range: 5–22), 13.9 ± 5.1 (range: 5–25), 11.5 ± 3.5 (range: 4–20) and 11.1 ± 2.8 (range: 4–20), respectively.

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Table 3. Mean score for each item of BMQ subscale (n = 153).

https://doi.org/10.1371/journal.pone.0201776.t003

Self-medication and beliefs about medicines

Based on Table 4, the prevalence of self-medication with analgesics was 29.4%, with 95.6% of the participants took analgesics when necessary. Paracetamol was (42.2%) reported as the most frequently used analgesic followed by ibuprofen (15.6%) and mefenamic acid (13.3%) for self-medication in dental pain management. Meanwhile, the mean total QAQ point was 0.4 ± 0.8 (range: 0–4).

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Table 4. Frequency distribution of the items assessing self-medication.

https://doi.org/10.1371/journal.pone.0201776.t004

Table 5 presents mean scores of BMQ subscales among participants practising self-medication and those not practising self-medication. Participants practising self-medication with analgesics for dental pain reported more positive beliefs in Specific-Necessity (13.0 vs. 9.9, p = 0.001) compared with those not practising self-medication. On the other hand, participants not practising self-medication reported more positive beliefs in General-Harm (p = 0.006) and General-Overuse (p = 0.032) as compared with participants practising self-medication. However, no statistically significant difference was noted in Specific-Concern (p = 0.916).

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Table 5. Mean total score of BMQ subscales among participants who practised self-medication and those who did not.

https://doi.org/10.1371/journal.pone.0201776.t005

There was a significant positive correlation between beliefs in Specific-Necessity and total QAQ point (r = 0.290; p < 0.001). Meanwhile, beliefs in General-Harm (r = -0.243; p = 0.003) and General-Overuse (r = -0.203; p = 0.012) were negatively correlated with total QAQ point. No correlation between was found between Specific-Concern and total QAQ point.

Discussion

The present study attempted to investigate the prevalence of self-medication with analgesics and to provide a further insight on the relationship between beliefs about medicines and self-medication for dental pain. It was reported in this study that slightly more than one-quarter of the participants (29.4%) practised self-medication with analgesics. The prevalence found in this study is similar to the prevalence of self-medication (30%) reported in previous study by Simon et al., [10], and lower prevalence than a study by Jain et al., [11], where approximately three-quarter of the participants (72%) practised self-medication.

This finding supported the idea suggested by previous studies that the difference in prevalence of self-medication was attributed to the dissimilar clinical settings [10,11]. Recruited participants in this study were patients attending OHC. Similarly, patients presenting at oral health outreach programs were recruited in the study conducted by Simon et al., [10]. In contrast, the study conducted by Jain et. al. targeted customers visiting pharmacies [11]. The lower prevalence reported in this study and the study conducted by Simon et al., may be explained by the fact that not all oral health problems were eventually brought to the dentist’s attention as patients might experience pain relief after self-medicating with analgesics obtained from pharmacies [10–12].

Results indicate that participants practising self-medication with analgesics for dental pain reported more positive beliefs in personal need for analgesics and did not view medicines in general as harmful and overused. The present study also found a significant positive correlation between beliefs in Specific-Necessity and total QAQ point. This indicates that as the participants beliefs in personal need and concern regarding analgesics become stronger, they take a higher total weekly dose of analgesic. Similarly, as participants beliefs in viewing medicines in general as harmful and being overused become stronger, they take a lower total weekly dose of analgesic.

These results were similar to a previous study by Sundell et al., [20], who assessed BMQ-General among the general population in relation to the use of Over-The-Counter medicines. According to Sundell et. al., individuals who took Over-The-Counter medicines had higher beliefs in the benefits of medicines but lower beliefs in viewing medicines as harmful and overused [20].

In view of these findings, the association between self-medication and beliefs in Specific-Necessity, General-Harm and General-Overuse could be attributed to the fact that patients with high positive beliefs about analgesics (Specific-Necessity) and low negative beliefs about medicines (General-Harm and General-Overuse) tend to perceive analgesic as a potential cure to dental pain. These beliefs lead to their decision to choose self-medication with analgesics as a coping action for dental pain [14,15].

However, beliefs in Specific-Concern was not significantly associated with self-medication and total QAQ score although it was considered as one of the negative beliefs. Patients with stronger beliefs in Specific-Necessity may recognise the potential benefits and role of analgesics in protecting their present and future oral health against deterioration. Moreover, nearly all patients in this study who practised self-medication took analgesics only when necessary. This suggest that they self-medicate with analgesics regardless of their concerns about the potential adverse consequences of taking analgesics such as the long term effects or worried of becoming too dependent on analgesics [14,15]. Another reason could be mild and episodic nature of dental pain as reported by majority of the study participants.

Paracetamol (also known as acetaminophen) was the most commonly used analgesic by patients with dental pain in this study. Paracetamol decreases acute dental pain [24] and is commonly used by patients who have dental pain [25–27]. The problem of overdose with paracetamol is frequently reported by previous studies [25–27]. In a recent study by O’Sullivan et al (2018) found that 38% of overdose patients treated in accident and emergency departments are caused by dental pain [25]. We recommend that dentists should refer to relevant guidelines on prescribing analgesics for dental pain [28,29]. No doubt the practice of self-medication provides benefits but it is also associated with potential risks including drug-drug interactions and misdiagnosis that can lead to severe complications [30,31]. Therefore, dentists should consider taking complete medication history including self-medication.

Strengths and limitations

There were some limitations in this study that need to be addressed and taken into consideration while interpreting the results. Firstly, there might be recall bias as subjective instrument was used to assess patient’s actual use of analgesics. In addition, non-probability sampling used might lead to selection bias among participants. Moreover, BMQ-General showed poor internal consistency which was probably due to the small number of items included. Furthermore, this was a single-centre study where the target population was limited to patients attending OHC. Thus, the results obtained might not be a good representative of a larger population.

Despite these limitations, there were some strengths in the present study. To the best of our knowledge, this was the first study conducted in Malaysia assessing the relationship between beliefs about medicines and self-medication with analgesics in dental pain management. Besides that, data was collected via interviewer-administered data collection form. Utilising an interviewer-administered data collection form is of substantial importance to minimise potential bias as participants were given the opportunity to clarify any doubts [32].

Conclusions

The study found that adult patients attending Oral Health centre at International Medical University, who practised self-medication had stronger beliefs about the benefits of medicines and weaker beliefs in viewing medicines as harmful and overused. No significant difference between those practising self-medication and those not practising in terms of beliefs in Specific-Concern. It is crucial to confirm whether beliefs about medicines are associated with self-medication as these findings can provide guidelines in public education to improve the safety aspects of self-medication. Upon considering the strengths and limitations, future research with relevant modifications such as targeting a larger population in different clinical settings is certainly needed to further confirm the results reported.

Supporting information

Acknowledgments

We would like to thank all the participants who took part in this study. We are also thankful and appreciated the help and support provided by the students and staff working at the Oral Health Centre, International Medical University throughout this research study.