Introduction

Pharmaceutical expenditures are one of the fastest growing components of healthcare costs [1] and are a challenge for healthcare systems [2, 3]. The cost of generic medicines is usually lower than that of their brand name alternatives [4]. Therefore, shifting to the generic medicines, which are released to the market after the expiration of the patent of the original brand name drug [5] and are pharmacologically equivalent to the original drugs [4], may play an important role in containing pharmaceutical costs [5] and improving medicine access and affordability [2, 6].

Iran’s health insurance systems reimburse the lowest price of the medicines that are available as generics; therefore, patients should pay the difference in costs when brand name medicines are dispensed. Based on decisions made by pharmacists and patients, pharmacists in Iran can legally substitute generics for brand name drugs, but such substitution is not mandatory [7]. In recent years in Iran, total health expenditures increased, but the public sector share of pharmaceutical expenditures decreased [8]; the increasing trend of the use of brand name drugs has led to an increase in patients’ out-of-pocket expenses to >60 % of total health costs [9]. In Iran, the market share of drug sales is split between multinational companies (≈40 %) and Iranian generic manufacturers (≈60 %) [10]. Generic utilisation in Iran, therefore, results in benefits for the healthcare system and also improves the national economy.

Faced with the increase in the pharmaceutical expenditures, many countries are looking for effective strategies, such as switching to generic medicines, to reduce costs [5]. Apart from government policies and regulations, this strategy is influenced by perception and behaviour of patients, pharmacists and physicians. More specifically, physicians, the main decision makers in healthcare systems, play a pivotal role in generic substitution [1, 6, 11].

Physicians’ prescribing behaviour is considered an affecting factor in improving generic utilisation. Since the physicians are the most trusted healthcare professionals [12, 13], and patient adherence to their advice is high [14], consumer acceptance of generic substitution will be increased if such substitution is done by physicians. Thus, prescribers play an important role in decreasing healthcare costs [15], as their beliefs and attitudes toward generic substitution [16] influence the use of generics. Several factors play significant roles in the physicians’ prescribing behaviour. For example, drug advertising and marketing can influence the choice of brand name medicines [17]. Moreover, negative concerns about the quality of generic medicines may lead physicians to avoid generic prescribing [18, 19]. However, the cost difference between generic and brand name drugs is a major factor in the acceptance of generics by physicians [20].

In the Iranian healthcare system, physicians are allowed to prescribe either brand name or generic medicines; however, healthcare insurance organisations reimburse only generic medicines. In this study, the researchers attempted to evaluate physicians’ perception of generic medicines, as well as evaluate its relationship with their demographic characteristics and other underlying factors. It is hoped that the findings of this study will generate baseline information to help policy makers control pharmaceutical expenditures through the increase use of generic substitution.

Methods

The data were gathered from a descriptive, cross-sectional survey conducted in Tehran in 2014. One thousand practicing physicians in Tehran, randomly selected from the Iranian medical council registry database of 3500 physicians, were invited to participate in this research via telephone. The questionnaire was delivered to 410 physicians who accepted to participate; this number of participants would achieve the sufficient sample size of 380 (calculated using the Cochrane equation). The questionnaires were delivered by the research team to the physicians in a previously arranged meeting and were completed during the meeting. The data gathering process took ≈5 months.

The self-administered questionnaire targeted physicians’ perception of generic medicines, their demographic characteristics, and other background factors. The questionnaire included 21 questions: three concerning physicians’ general perception toward generic substitution; and 18 (in six sections) covering physicians’ beliefs and perceptions concerning the efficacy, safety, cost containment, patient acceptance and marketing of generic medicines, and the role of government in promoting generic substitution. Questions were answered using a 4-point Likert scale (where ‘1’ was strongly disagree and ‘4’ was strongly agree). In addition, respondents’ demographic characteristics (i.e. gender and age) and other background data (i.e. educational level, years of experience and workplace) were collected.

The draft of the questionnaire was developed based on the literature [21–23] and expert opinion. To check its face and content validity, it was reviewed by five general practitioners and five specialists who had at least 10 years of experience. On the basis of their feedback and factor analysis results, the number of questions was reduced from 35 to 21. Using Cronbach’s alpha coefficient on 30 completed questionnaires indicated that the reliability of the revised questionnaire was acceptable, and the final questionnaire was then used to gather data.

Descriptive and inferential statistics were performed on collected data using SPSS 16.0.0. The primary view of the data was provided by descriptive statistics (e.g. frequency, mean, and standard deviation). Confirmatory factor analysis was used to test the unidimensionality of the main factors so that all the items reached a factor loading of >0.5. Factor loadings represent the correlation between each item and its related dimension, which provides strong evidence that appropriate items have been selected to measure each dimension.

Results

Of the 1000 selected physicians, 410 completed the questionnaire (response rate 41 %). The demographic characteristics of the respondents are shown in Table 1. Physicians’ general beliefs and attitudes regarding generic substitution are shown in Table 2. More than 70 % of participants tended to prescribe generic medicines if they were sure about their equivalency. However, when they were asked about domestically produced medicines, they were not satisfied by generic substitution, with >75 % of them reluctant to prescribe domestically produced medicines. Most (≈60 %) physicians disagreed with pharmacists’ right to substitute generic medications when dispensing.

Table 1 Demographic characteristics of responding physicians (n = 410)
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Table 2 General opinion of responding physicians (n = 410) toward generic substitution
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Table 3 shows descriptive statistics for each question, including the response frequency, mean and standard deviation, as well as the factor loading for each dimension. As seen, low standard deviation of all items indicated an acceptable level for further analysis. The results of confirmatory factor analysis showed that Kaiser–Meyer–Olkin (KMO) values were >0.5 for all dimensions and the percentage variances were at least 0.5. Moreover, factor loadings for all items were >0.5. Most responding physicians were not sure about the efficacy of generic medicines [question (Q) 1], which reached 79 % with regard to domestically produced generics (Q3). A majority (72.2 %) of respondents thought that brand name medicines were superior in efficacy (Q2). Although concerns regarding the safety of generic medicines were not as evident as those regarding their efficacy, ≈60 % of physicians showed their negative perception of generic safety by choosing ‘strongly agree/agree’ as a response for Q4–6.

Table 3 Descriptive and reliability analysis of the six sections (dimensions) of the questionnaire (Cronbach’s alpha = 0.78)
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According to participants’ perspectives regarding the cost advantages of generic medicines (Q7–8), cost containment is a considerable factor for prescribing generics (60–68 %), and according to responses in Q9, it was a more attractive option for low-income patients (81 %). With regard to the patients’ acceptance of generic medicines (Q10–12), the responses showed an approximately equal split with regard to agreement and disagreement for questions related to the age, gender and level of education of patients. Regarding the effects of marketing (Q13–15), although >50 % of the participants expressed that advertising can increase generic utilisation, they mostly denied the effect of marketing activities on their own practice.

Finally, participants requested the support of government to improve the utilisation of generic medicines (Q16–18); >84 % thought that more scientific evidence about the safety and efficacy of generics in general and domestically produced medicines in particular can improve generic prescribing (Q16), and that such evidence can be a main driver for increasing the prescribing of generics (Q17). In addition, 77 % of the participants thought government could improve the utilisation of generics by training the public in their use (Q19).

Table 4 shows the correlation between participants’ perception of the different dimensions of the questionnaire and their demographic and background characteristics. Males and older physicians showed significantly more attention to patient acceptance of generics than females or younger physicians. Although there were not any significant between-group differences with regard to beliefs on generic safety, specialists had more positive perceptions of the efficacy of generic medicines than general practitioners. The perception of marketing effects differed according to: years of experience; and workplace (i.e. physicians practicing in public clinics believed marketing had less power than those in the private sector).

Table 4 Correlation between participants’ characteristics and response
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Finally, priority analysis of the six sections of the questionnaire using the Friedman test and a level of significance of 0.01 (2-tailed) found the government’s efforts on evidence sharing and public training to be the most significant factor affecting generic prescribing. This was followed by cost containment size, beliefs on generic efficacy and safety, patient compliance and, lastly, marketing activities. It should be noted that priority analysis in the Friedman test is based upon the mean rank of dimensions without considering the mutual effect of other dimensions; hence, other analytical approaches may result in different findings.

Discussion

The increasing costs of pharmaceutical products in recent years presents a challenge to healthcare systems [2, 3]. Over recent decades in Iran, the annual sale value of pharmaceuticals has grown by 20–30 % [24], with imported brand name drugs accounting for ≈40 % of the market share [8]. Many policies, including granting pharmacists the right to substitute generic medicines, have been employed by governments to increase the utilisation of generics [25]. However, these policies may have temporary effects [26] if physicians, the main decision makers in brand name/generic selection, do not properly support such policies.

According to the results of this study, Iranian physicians do not support the use of brand name medicines, with >70 % preferring to prescribe generics when equivalent alternatives are available. However, reluctance to prescribe generics was high when products were produced domestically; only 24 % of physicians tended to recommend locally produced products. This discrepancy suggests that physicians assume that domestically produced medicines are not equivalent, and serves as an important alert to Iranian policy makers that increased efforts are needed to improve the image of domestic products. This is in agreement with a previous study conducted in India, which showed that physicians had a positive opinion of generic medicines, but, in practice, preferred the use of brand name products because of a lack of trust and information, as well as the insufficient regulatory framework in the country [27].

Moreover, this study found that physicians do not have a positive perception of generic substitution when the drug is dispensed at a pharmacy, with 60 % disagreeing with the right given to the pharmacists to substitute generic medicines. Similarly, in studies conducted in Australia [23] and New Zealand [28], physicians expressed their dissatisfaction with the rights given to community pharmacists to substitute prescribed medicines with generic ones. Other studies pointed out that physicians opposed generic substitution because of their concern about pharmacists’ ability to substitute safe and therapeutically equivalent interchangeable medicines, and some other studies highlighted physicians’ concerns about them losing control over the treatment process and the reduction in patient adherence [29–33]. This negative perception may have been intensified by non-adequate consultation by pharmacists [34–36].

Similar to physician perceptions in other countries [23, 37, 38], the efficacy of generic medicines is a major main concern of Iranian physicians (79 % are concerned about the efficacy of domestically produced generics, and 72.2 % thought brand name medicines were superior in efficacy to generics). They were also concerned about the safety of generics, with 60 % of the physicians indicating they had negative perceptions of generic safety; in the Indian study, 77 % of physicians were similarly concerned about the safety of local products [27].

The significant differences between responses in various demographic groups may be useful when designing further investigations. For example, males and older physicians showed significantly more attention to patient acceptance of generic prescriptions. However, their opinion may be negatively influenced by patients’ complaints [37]. Although there was not any significant difference concerning the beliefs in safety in different groups, specialists had more a positive perception of the efficacy of generic medicines than general physicians, which may be explained by their deeper knowledge of equivalency studies [27].

Drug advertising and marketing by pharmaceutical companies [17, 22] (e.g. incentives such as promotional gifts and financial rewards, free samples, small gifts, or financing conference participation) may influence physicians’ prescribing patterns. Although it cannot be stated that physicians prescribe on the basis of the rewards that they receive from the companies, such rewards help physicians remember the brand names of the companies’ drugs [39, 40]. The participants of this study mostly accepted marketing activities as a promoting factor in generic prescribing in a similar fashion to physicians in India or UK [27, 41]. However, they did not accept its effect on their own practice, which may be due to their awareness of ethical issues. This point of view was significantly less seen among the physicians’ practicing in public sectors such that they agreed more with the effect of marketing activity on prescribing behaviour. This finding is consistent with the previous study that highlighted the effect of marketing on physicians’ behaviour [42].

As was discussed earlier, physicians generally did not show high trust in the efficacy of generic medicines. Furthermore, this was even worse in the case of domestically produced medicines. In other words, the number of physicians unsatisfied with the efficacy of locally produced medicines reached about 80 %, which was significantly higher among general practitioners than among specialists.

Although, in line with other studies [20], Iranian physicians do not have a positive perception of generic medicines, the cost of generics versus brand name drugs is a major factor in the acceptance of generics by physicians; 60 % of the respondents stated that cost differences were the main driving factor in prescribing generics, which reached 80 % for low-income patients. In a similar fashion, a Swedish survey [43] showed that 68 % of physicians approved of generic medicines, because they thought that generic substitution would reduce the cost of medicines in the healthcare system. Hence, physicians’ awareness about cost differences is a key driver in prescribing generics [44].

Finally, the findings, using Friedman’s analysis, show different weights for diverse dimensions of physicians’ perceptions of generic substitution. More specifically, the government’s role was the most important factor affecting generic prescribing, which was followed by cost containment size, beliefs in efficacy and safety, patients’ compliance, and marketing activities. To this end, physicians placed emphasis on the government’s role in public training and in evidence sharing for improving public perception of generic medicines. In addition, they strongly asked the government to provide evidence in terms of the efficacy and safety of generic medicines. With this in mind, having efficient pharmaceutical regulations, competent drug authorities, as well as effective communication channels between the authorities and physicians to ensure them about the safety and efficacy of generic medicines is highly recommended. This is in line with other studies that showed that the majority of physicians asked regulatory authorities to meticulously and continually check the quality of the products that are locally manufactured [27].

Limitations

The results may not be generalised to other contexts because of the limited sampling location. Moreover, as there are no published data on demographic and other related characteristics of the studied population, response bias (if any) could not be evaluated.

Conclusion

Based on the findings of this study in Iran, physicians, the main decision makers with regard to medicine selection, do not have positive perceptions relating to the efficacy and safety of generic medicines; in addition, neither marketing activities nor patients’ acceptance is an important factor in preventing generic prescribing. Therefore, the government plays a critical role regarding public training and reassuring healthcare professionals about the safety and efficacy of generic medicines in general and about the locally produced ones in particular.