Self medication with antibiotics or the use of non-prescribed antibiotics including leftover antibiotics is common in both developed and developing countries, in which the point prevalence ranges from 3% to 75% [1–5]. Non-prescribed antibiotics may be used inappropriately due to a lack of health professional supervision. For example, previous studies in Jordan [6], in Lao People's Democratic Republic [7], and in European countries [8] found that non-prescribed antibiotics mostly were used for treating the common cold, a viral condition for which antibiotics treatment is ineffective [9]. As a consequence, self medication with antibiotics may be associated with undesirable effects, such as decreased effectiveness and worsening clinical conditions and has become an important factor driving antimicrobial resistance [10]. Such consequences potentially jeopardize the health of the individual who self-medicates as well as society as a whole.

Problems related to self medication with antibiotics particularly in the developing world, are complex as they are linked to other issues, such as poverty, lack of access to medicines and information regarding medicines, poor quality of health care facilities, and weak implementation of regulation related to medicines. For example, limited purchasing power is associated with self medication with antibiotics among the population in Kerala India [11], Nigeria [12], the Philippines [13], Latino adults in the United States of America [14], and the non-Arab population in the United Arab Emirates (UAE) [15]. In addition, because of economical constraints, poor people may purchase insufficient amounts of non-prescribed antibiotics [16]. They may be forced to purchase antibiotics without a prescription at a low price in common kiosks (i.e. with lay sellers), which can be poor quality or counterfeit. Other issues related to poor quality and inadequate access to the health care service also exist, such as, waiting times, limited supply of medicines, unacceptable practices of health professionals in health care facilities, the high cost of transportation to reach health centers, and having no health insurance [5, 11]. Such issues potentially persuade people to self medicate instead of seeking a medical consultation.

Research understanding patterns of utilization of antibiotics and factors associated with such use is essential for improving the appropriate use of antibiotics particularly in less developed countries. Such epidemiological information is useful in guiding the formulation of educational interventions [17], especially to understand features of antibiotic use, to identify possible causes, and to define goals of future interventions [18].

In Indonesia antibiotics are legally categorised as prescription-only medicines whose sale is restricted to pharmacies [19]. Drug stores are not allowed to sell prescription-only medicines, while kiosks can only sell over- the-counter (OTC) medicines, such as paracetamol and vitamin C [20]. However, antibiotics can be easily purchased without prescription and are accessible from those vendors.

Although information on the prevalence, patterns of utilization of non-prescribed antibiotics and socio-demographic factors has been available in both developed and developing countries, in Indonesia such studies are uncommon. One previous study [5], in 2001 to 2002, reported the patterns of self medication with antibiotics and socio-demographic factors of such use among individuals visiting public healthcare facilities. However, that study was not a population-based survey and therefore was neither representative nor could exclude sample bias. In addition, that study did not explore the reasons of self medication using antibiotics, which are important for understanding such behavior. This present study is the first population-based survey in an urban area in Indonesia to investigate the prevalence, utilization patterns of self medication with antibiotics including the reasons, and socio-demographic factors of such use.

This population-based survey examined randomly selected adults applying a rigorous sampling procedure. The 90% of response rate indicates that the sample is reasonably representative of adult people in Yogyakarta City. The involvement of the head of neighborhoods in knocking on doors, as expected, improved the response rate.

This study identified a 4-week period prevalence of 7.3% for using non-prescribed antibiotics and highlighted patterns of use where amoxicillin, ampicillin, fradiomicyn-gramicidin, ciprofloxacin and tetracycline were the self-medicated antibiotics and were purchased mainly in pharmacies. These antibiotics were used to treat a variety of minor symptoms, such as the common-cold, cough, sore throat, and fever, for mostly less than five days of use. Such practices were based on reasons of previous successful experience, saving time and money, and information obtained from health professionals, lay people, and printed materials.

We acknowledge some limitations in this study. Although this study uses the population of Yogyakarta as its sampling frame, generalization to the whole population of Indonesia should be done carefully. The area of this study, Yogyakarta City, is an urban with a high population density and a mostly literate population. Thus, results may be readily generalizable to other urban areas of Indonesia. For example, the pattern of SMA found in two big cities in Java Island is similar with those in this current study [5]. The situation may well differ in rural areas, however. Further, the use of antibiotics in this study is self reported, and therefore there are some issues regarding subjectivity and imprecision. However, such issues were minimized by using a four-week recall period, which has been extensively used by other similar studies [5, 6]. The sample size calculation was based on an estimated period prevalence of self medication with antibiotics of 50%, the midpoint of estimation in the literature. This approach had short comings, however, as the figure is very dependent on the length of the recall period. Unfortunately, our calculation did not account for the variation in these periods. Moreover, because of limited resources a larger precision (d = 0.05) was used to calculate the sample size and a probability proportionate to size (30% and 5% of sub-districts and neighborhoods, respectively) was applied to limit the numbers of clusters in the second and third stages. However, the involvement of all clusters (districts) of the first stage could minimize sample bias [23]. In addition, a quarter of the respondents did not mention their current employment thus this question may be sensitive in the local socio-cultural context. People would perhaps be unwilling to be honest when they are unemployed or non-economically active or employees of informal/casual sectors. Despite such limitations, as a consequence of representativeness of the urban population following the inclusion of a random sample, information yielded from this study is invaluable in describing the use of non-prescribed antibiotics.

A one-month period prevalence of self medication with antibiotics in this study is comparable to that of a household survey in Jordanian population (a one-month period prevalence 9%) [6]. Higher period prevalence has been reported in other developing regions, for example, Mexico (2-week period prevalence 18%) [2] and Sudan (4-week period prevalence 48%) [3]. A four- week period prevalence of 7.3% found in this present study is higher than the previous Indonesian study (a 4-week period prevalence of 3%) [5]. This finding indicates a potential increase in self medication with antibiotics among Indonesians, particularly in urban areas. Further, a four-week period prevalence of 7.3% indicates that an even larger proportion of the urban population in Indonesia would self medicate with antibiotics annually.

Generally, the patterns and the reasons of using non-prescribed antibiotics found in this study are similar to those in other less developed countries [1, 2, 6, 26] and in some European countries [27]. Such patterns, for example, the use of non-prescribed antibiotics for the common-cold, indicate inappropriate use. They also indicate overprescribing of antibiotics as people do tend to duplicate their previous prescriptions for self medication [28, 29]. Although in Indonesia and elsewhere prescription scripts are retained in pharmacies, people commonly make notes of prescribed medicines for future reference if similar medical problems reoccur [28, 29]. In Indonesia there is a promising intervention program to improve rational prescription of antibiotics particularly for URTI (Upper Respiratory Tracts Infection) known as Monitoring, Training and Planning (MTP) conducted by the Centre for Clinical Pharmacology and Drug Policy Studies. The program has been implemented among health professionals in hospitals in Yogyakarta and has been successfully decreased antibiotics prescription for URTI. Such programs should be applied extensively with the involvement of health professionals in both public and private health service; and private practices.

The patterns of use also indicate inadequate information given to patient as well as to the public. In most developing countries, drug information given by health providers in both primary health care centers and hospitals is not yet optimal [30]. In addition, pharmacy personnel tend to be businessmen rather than professional. When antibiotics are requested by consumers requests are neither refused nor questioned [16]. Since antibiotics are legally grouped as prescription-only medicines, information about such medicines is, unfortunately, not readily available to the general public, but only to health practitioners. It is different with the over-the-counter (OTC) medicines or general sales, where information about the product can be easily accessed through the packed inserts and mass media advertisements. Currently, there is an initiative to locate Indonesian pharmacists in primary health care centers. Such an initiative is promising, particularly to provide adequate information related to medicines including antibiotics and to improve the quality of health care service in general.

Economic considerations are an important factor influencing SMA behavior [29]. There is mixed evidence on the association between lower income and SMA behavior [1, 11–15, 31]. In this study household income level is not associated with either intent or actual SMA. However, this issue is significant for further investigation in Indonesia because a substantial proportion of the whole Indonesian population is poor [21]. Further, as found in this study, having no health insurance is a significant factor associated with self medicating with antibiotics, which is consistent with a previous Indonesian study [5]. Unfortunately, only approximately 30% of the whole population is covered by health insurance [31].

Self medication with antibiotics is common among urban population of Indonesia, in which being male and having no health insurance were highlighted to have intent of such use. Underlying factors of why people self medicate with antibiotics should be further examined to better understand this behavior. Given that past experience in using antibiotics is the main reason of the actual SMA, people should be informed that previous antibiotics used are not always appropriate to be used for future medical problems. Impact of health insurance coverage on such behavior should also be further investigated.