Study design: This cross-sectional epidemiological study was carried out from April 2016 to June 2016 based on survey design. The inclusion criteria were that participants had to be Iranian between 20 to 60-year-old and with the ability to complete the questionnaire in Persian language. The purpose of research was described to all the participants and informed consents were obtained.

Participants: Iran consists of 31 provinces, and near eighty million people. We selected 12 provinces randomly{Isfahan (known as the half of the world), Qom, Tehran, Gilan, Qazvin, Sistan, Central Khorasan, Khoozestan, East Azarbayjan, Alborz, Yasuj and Ardabil}. Sample size was calculated with formula: n=z^2*Pq/d^2 and using the convenience sampling method 950 participants were enrolled in the study (about 80 participants from each province).

Data Collection: In order to gather data a researcher-made questionnaire was used based on the aim of research and according to the scientific literatures [4,5,7]. It was composed of three sections: A) Antibiotic consumption behaviour; B) Knowledge about antibiotics; and C) Demographic data. In order to achieve the psychometric criteria, content validity and reliability were evaluated.

Ten experts (pharmacist and PhD in health education) viewed the questionnaire in order to approve the content and face validity. The alpha-cronbach for test-retest reliability in twenty participants was 0.85. Out of total 950 participants, 683 (71.8%) answered yes to the first question in section A; (Did you already have an arbitrary use of antibiotics?). These participants were asked to complete all sections and the others were conducted to answer the sections just B, and C. The knowledge assessment questions had two options; “Yes”, and “No”. Questions 1 to 8 scored as; 1 (Yes) and 0 (No) and question 9 and 10 scaled as; 0 (Yes) and 1 (No). Minimum and maximum expected score for knowledge was 0 to 10, respectively. Direct contact with the respondents allowed us to inform them about the research’s objectives and assure the respondents about the anonymity and confidentiality of research.

The Statistical Package for Social Sciences software (SPSS, version 16.0) was used for statistical analysis. All gathered data were coded and entered in, then using descriptive analysing methods means and standard deviations of variables were calculated and next, their differences according to gender, literacy and residency were analysed with χ² parameter. A p-value less than 0.05 was considered significant.

Demographic Data: Demographic data of the participants are shown in [Table/Fig-1]. The majority of respondents (n=608) were in 20-40-year-old. About 52% (n=493) were male and near to 50% (n=465) were married. Near to 92% (n=873) stated to have an insurance and most of the respondents (n=701) were graduated.

Self-report knowledge: Participants’ knowledge about antibiotics is shown in [Table/Fig-2]. Mean and standard deviation of participants’ knowledge was 4.85±0.65. All participants stated that they have not been educated about antibiotics. Most of participants were unaware about better time (610, 64.3%), importance of on-time consumption (582, 61.3%), common side effects (702, 73.9%), wide-spectrum one (761, 80.2%), and about better dose (630, 66.4%) of antibiotics. Near to 81% (n=768) of participants stated that high-dose antibiotics lead to immediate healing.

Self-report practice: As shown in [Table/Fig-3], out of 683 participants who already had arbitrary use of antibiotics, 213 (31.1%) and 195 (28.5%) participants stated that they have taken antibiotics arbitrarily 2 and 3 times in recent year, respectively. Also, 51.2% (350) reported that they do not understand the antibiotics instruction. The most common reason to use it arbitrarily was its accessibility (432, 63.2%). More than half percent of participants stated that the feasibility of consumption leads to arbitrary use (386, 56.5%). According to the participants’ statements, sore throat (432, 63.2%), and running nose (478, 69%) were the common situation of arbitrary use. The majority of participants used to select the antibiotics (432, 63.3%), and measured the dose (349, 51%), too, based on the previous physician’s orders. More than 60% of participants stated that they have changed the doses during self medication. More than half (53.8%) used to changed the type of antibiotics, arbitrarily. Amoxicillin (Cap.), Ampicillin (Cap.), Metronidazole (Tab.), Erythromycin (Syr.), and Tetracycline (Oint.) were the most common antibiotics.

Correlation and Relation: The relations between knowledge, demographic characteristics, and some behavioural items are shown in [Table/Fig-1,4]. The participants in academic literacy level revealed more knowledge about antibiotics and there was a significant difference between mean of knowledge and the two literacy levels (p=0.034). There was not any significant difference between mean of knowledge according to other demographic data [Table/Fig-1]. Also, there was a significant difference between mean of knowledge and arbitrary use (p= 0.002), changing the dose (p=0.04) and changing the type of antibiotics (p=0.038) {shown in [Table/Fig-4]}.

It is true that arbitrary use of antibiotics is a common problem among Iran and other developing countries. Although there is not any precious figure about the rate of self-medication among Iranian, informal reports have mentioned that Iranians have the highest rate of it [11,12]. In the current study we aimed to explore the knowledge and practice about antibiotics consumption among Iranians. The results showed that the majority of the participants did not possess the adequate knowledge about antibiotics consumption in addition to their misconception about antibiotic usage. Most of the participants used left-over antibiotics. In a cross-sectional study in 2016, Jamhour A et al., examined the antibiotic knowledge and self-medication practices in a developing country (Lebanon), explored that 61% of the respondents thought that antibiotics should be taken for common cold. Self-medication significantly correlated with a lower educational level. Those with lower knowledge have worst behaviour [10]. Also, Banerjee I et al., in the similar cross-sectional study among medical students in Nepal found the same results. They recommended improving medical student’s awareness about the pros and cons of self-medication in order to motivate them for rational use of antibiotics [11].

Exploring the reasons for self medication is very important. In the current study the majority of participants used the leftover antibiotics for sore throat and running nose. They tried to change the dose and type of antibiotics during self medication. In addition, individual with higher knowledge had lower tendency to self-medication. All of the participants stated that they have not been educated about antibiotics. In a systematic review and meta-analysis about the burden, risk factors and outcomes of self medication in developing countries, Ocan M et al., found that the major sources of antimicrobials included, pharmacies, leftover drugs and drug shops. Also, they explored that the main determinants of antimicrobial self-medication include, level of education, age, gender, past successful use, severity of illness and income [12].

Jorgji K et al., in 2014 conducted a similar study aimed to explore the self-medication among young adults. They found that the most common reasons for self-medication were fever, sore throat and cough. Also, they observed that the most common source of information regarding self-medication is the pharmacy and most common antibiotic used as self-medication is amoxicillin [13]. Shah SJ et al., in a cross-sectional study explored the self-medication with antibiotics among non-medical university students of Karachi. They found that about 61% of the participants did not meet the adequate knowledge about antibiotics; also, amoxicillin was the most self-prescribed antibiotic [14].

Biswas M et al., in a similar cross-sectional study in Bangladesh, found that more than 26% of the participants had experienced self medication with antibiotics. The key reasons for the self-medication of antibiotics was the pre-experience, suggestions from others and knowledge of the antibiotics. The perceived symptoms to use the antibiotics were dysentery, diarrhea and food poisoning; cold, cough and fever; infection, dental caries and toothache; irritable bowel syndrome, acne, ear and throat pain [15].

In the current study, most of participants strongly believed that a high dose of antibiotics leads to immediate healing of infections. The most common reasons for antibiotic use in Yemen, Saudi Arabia, and Uzbekistan were cough and influenza. Belkina T et al., also found that awareness of the dangers of antibiotic use correlated inversely with self-medication, understanding of the appropriate use of antibiotics was limited. Forty-nine percent of respondents discontinued antibiotics when they felt better [16]. In a similar study in Nigeria, Enato EF et al., explored that the majority of the ill persons self-treated by using antibiotic and antibacterial drugs. Symptoms such as fever, chills, joint pain, headache, gastrointestinal problems and upper respiratory symptoms were most common situation for self medication [17].

The current study had some limitations. All data was gathered via a self-report questionnaire; so it is obvious that some biases may have taken place. The survey was conducted nationally among 12 provinces in Iran, with large sample size of 950 participants who were selected in multilevel sampling methods. However, in order to save time, we used a short and valid questionnaire; which might not covered all aspects of topic.

The current study revealed that the average knowledge of Iranians about antibiotics is not satisfactory and most of them take it arbitrarily. It is very important to conduct community based educational program in order to develop a rationalized consumption of antibiotics. Further studies in this regard are recommended strongly.