The use of medicines in healthcare facilities is essential for treating various diseases [1] [2] . However, evidence has shown that medicines have been used irrationally in managing diseases [3] [4] . Irrational use of medicines occurs with polypharmacy, with the use of wrong or ineffective medicines, or with underuse or incorrect use of effective drugs [5] . These actions can adversely impact the quality of medical therapy and cost, and they may also cause adverse drug reactions or negative psychosocial impacts [6] . Alongside this, irrational use of medicines can give rise to many problems, including increased mortality, morbidity, poor treatment outcomes and wastage of healthcare resources [3] .

The impact of irrational use of medicines is a global public health problem that may influence the resistance of pathogens to antimicrobials, the risk of hospitalization, increased costs, adverse effects, and waste of resources [7] - [10] . The World Health Organization (WHO) reported that approximately 50% of all medicines are prescribed irrationally [11] [12] . Hence, to promote the rational use of medicines in healthcare facilities, the WHO in collaboration with the International Network of Rational Use of Drugs (INRUD) developed core drug prescribing and use indicators [13] - [15] . The WHO and stakeholders concluded that to promote rational use of medicines, patients should receive medications appropriate to their clinical needs, in doses that meet their requirements, for an adequate period, and at the lowest cost to them and their community [16] .

The WHO’s core drug use indicators include prescribing indicators, patient care indicators and health facility indicators [13] [17] . Drug use indicators are a set of standardized indices used to measure drug use in hospitals [18] . Medicine use indicators provide a measure of the optimal use of medicines and can help in correcting deviations based on the expected standards [19] . The WHO defines rational use of medicines as giving the right medicine, for the right patient, at the right dose, for the right duration and at the right (lowest) cost to them and their community [20] . Different studies have shown that most medicines are inappropriately prescribed or dispensed [12] [20] - [22] . Moreover, the association between increased misuse of antibiotics and the emergence and spread of resistant microorganisms has been confirmed by many studies [23] - [25] .

Prescribing indicators measure the performance of healthcare providers in several key dimensions related to the appropriate use of medicines [14] [26] - [28] . The indicators are based on the practices observed in a sample of clinical encounters taking place in hospitals for the treatment of acute and chronic illness [29] . These include the average number of drugs per encounter which measures the degree of polypharmacy; the percentage of drugs prescribed by generic name which measures the tendency to prescribe by generic name; the percentage of encounters with an antibiotic prescribed and an injection prescribed which measures the overall use of two important but commonly overused and costly forms of drug therapy; and the percentage of drugs prescribed from the Essential Medicines List (EML) [30] [31] .

Rational medicine use (RMU) is essential to optimize the quality of healthcare delivery and resource utilization [32] - [34] . Consequently, studies have shown that prescribing indicators for the African region deviate significantly from the WHO recommendations [13] [21] [22] [35] - [39] . Notably, the deviations from the WHO recommended indicators in low- and middle-income countries (LMICs) could be because of an increased burden of infectious diseases, shortages of medicines, and understaffing of competent healthcare professionals [5] [13] [39] - [42] . Consequently, a shortage of medicines in healthcare facilities causes prescribers to usually prescribe irrationally [43] [44] .

The overuse and misuse of antibiotics contribute to the emergence of antimicrobial resistance (AMR) which tends to be a global public health threat [45] - [47] . The high prescribing of antibiotics has been reported in other studies [3] [48] - [50] . This is of great concern because most prescribed antibiotics tend to be inappropriate, especially in LMICs [21] [22] [51] [52] . Therefore, there is a strong need for strategies to be instigated to address this problem and reduce the emergence and spread of AMR [53] [54] . The development and implementation of antimicrobial stewardship (AMS) programs in hospitals are very essential to address the problem of AMR Furthermore, to curb AMR, countries must develop and implement their National Action Plans (NAPs), as guided by the Global Action Plan (GAP) on AMR [55] - [58] . Alongside this, hospitals must adhere to the set prescribing guidelines and antibiotic use following the WHO Access, Watch, and Reserve (AWaRe) classification of antibiotics [59] - [64] . The AWaRe framework promotes the rational use of antibiotics in healthcare facilities to prevent the emergence and spread of AMR [60] [63] - [65] .

In Zambia, despite the Zambian National Drug Policy's emphasis on promoting good practices, there exists a notable gap in information regarding Rational Medicine Use (RMU). Additionally, this is evidenced by several studies that highlighted instances of inappropriate prescribing practices [21] [22] [25] [35] [36] [44] [66] [67] . Consequently, there is still a paucity of information on the prescribing of medicines using the WHO/INRUD prescribing indicators in hospitals in Zambia. Therefore, this study evaluated the prevalence of antibiotic use and adherence to the WHO prescribing indicators at the Request Muntanga Hospital in the Kalomo district of Southern Province, Zambia.

This study surveyed antibiotic use and the WHO/INRUD prescribing indicators of medicines at the Request Muntanga Hospital in Kalomo District of Southern Province, Zambia. As far as our understanding extends, this study represents the inaugural examination of the WHO/INRUD prescribing indicators for medicines and the frequency of antibiotic utilization within Kalomo District of Southern Province, Zambia.

Our study found that most patients, 61.3% were prescribed more than one medicine, indicating the high practice of polypharmacy. Our findings are similar to those reported in Ethiopia where most patients received more than one medicine [73] . Our findings are also in line with those reported in a study that was conducted in Korea where 46.6% of the participants in a cohort study had experienced polypharmacy [8] . This could be attributed to the burden of disease, non-adherence to treatment guidelines, a lack of prescriber financial incentives, inadequate or no continuous professional development (CPD) training for prescribers, and incompetence among prescribers, especially in LMICs. Consequently, polypharmacy must be practised carefully as it has the potential to cause adverse effects, risk for hospitalization, and may even lead to death [8] [74] - [77] .

The current study found that the average number of drugs per encounter was 2.1. This average number deviates from the standard provided by the WHO, according to which, the average number of drugs per encounter should be between 1.6 and 1.8 [14] [15] . Another recent study conducted in Zambia found the average number of medicines prescribed per patient encounter to be 2.5 [35] . Our study findings are consistent with results reported from previous studies where there was a high average number of medicines prescribed per encounter including 3.7 in Tanzania [78] , 3.6 in Nigeria [79] , 3.48 in India [80] , 3.2 in Uganda [27] , 2.8 in Pakistan [81] , 2.5 in Egypt [32] , and 2.3 in Ethiopia [18] . The average number of medicines prescribed in our study and similar studies is higher than the one recommended by the WHO. This shows that most patients were on polypharmacy which has implications including adverse drug effects on the patient. A study in Pakistan reported a low (1.4) average number of medicines prescribed per encounter indicating a low prescribing of medicines in this patient population [24] . Our study findings and many similar studies demonstrated an increased use of medicines in disease management.

The present study found that the prevalence of antibiotic use per encounter was 86.7%. The antibiotic use per encounter found in our study exceeds the recommended range of 20.0% to 26.8% recommended by the WHO [14] [15] [82] . Our study findings are slightly similar to those reported in other studies, including 79% in Eritrea [83] , 81.5% and 82.3% in Pakistan [24] [84] , 82.5% in Ethiopia [39] , and 88% in Tanzania [78] . Conversely, our findings contrast those reported in Ethiopia where encounter with antibiotics was 69.6% [85] , 66.22% in Uganda [27] , 66% in India [86] , 54.5% in Eritrea [87] , 44.7% in Nepal [82] , and 41.1% in Tanzania [78] . The overuse and misuse of antibiotics in hospitals is a driver of AMR [88] - [92] . The findings from our study and similar studies indicate the need to instigate and strengthen AMS programs in hospitals to promote the appropriate use of antibiotics [93] - [98] .

In the current study, 17.8% of encounters were injectable medicines, which was in line with the WHO recommendations of 13.4% - 24.1% of the prescriptions to contain injectable medicines [14] [15] [17] . A study in Ethiopia found that 6.3% of the encounters were injectable medicines, which was lower than the WHO recommendations [85] . Eritrea also reported a low use of injectable medicines, at 6.6% [87] . However, our findings were lower than those reported in Ethiopia where an encounter with injectable medicines was 38.1%, indicating non-adherence to the WHO prescribing indicators [99] . A study that was conducted in Uganda reported that 25.22% of injectable medicines were prescribed, indicating a higher number of injections than the recommended standard by the WHO [27] . The high use of injectable medicines reported in other studies may have implications including a reduction in the quality of medical care, concerns about patient safety, increased potential to cause adverse effects, and wastage of resources [100] .

Our study found that doctors prescribed 38.9% of the medicines under their generic names. This finding deviated from the WHO core prescribing indicators that stated that all medicines (100%) must be prescribed by their generic names [14] [15] . An earlier study conducted in Zambia found that 56.1% of the medicines were prescribed by their generic names [44] . Additionally, a recent study in Zambia found that 96.5% of medicines were identified by their generic names [35] . The rate of prescribing medicines by generic names in our study was lower than the 97% reported in Eritrea [101] , 96% and 97.6% in Ethiopia [85] [102] , 62% and 90.48% in Uganda [27] [103] .

The current study discovered that 76.7% of drugs came from the ZEML Our findings fall short of the ideal WHO-recommended value of 100% [14] [15] . The rate of prescribing antibiotics from the National EML found in our study is similar to what has been reported elsewhere [103] . On the other hand, the rate of prescribing medicines from the National EML found in our study was lower than the 98% that was reported in a recent study in Zambia [35] , 100% in Eritrea [101] , 96.6% and 100% reported in Ethiopia [99] [102] , and 96.23% in Uganda [27] . The deviations from the recommended treatment guidelines may promote irrational medicine use and contribute to the emergence and spread of AMR [7] [104] [105] .

Our findings showed that the prescribers at Request Muntanga First Level Hospital in the Southern Province of Zambia did not adhere to any of the WHO core prescribing indicators. Consequently, our findings necessitate the instigation and implementation of strategies to promote adherence to prescribing guidelines at the hospital, particularly as reported by other researchers [36] [37] [58] [60] [106] . We believe educational and training interventions through AMS programs in hospitals can improve the prescribing habits of medicines and adherence to treatment guidelines to reduce the emergence and spread of antimicrobial-resistant infections [53] [54] [58] [107] - [112] .

We are aware that our study had some limitations. The study was conducted at one hospital in the Southern Province of Zambia, hence, this affects the generalisation of the findings across all hospitals in Southern Province and Zambia at large. However, our findings can be used to instigate interventional strategies to promote rational prescribing and use of antibiotics.

This study found that there was low adherence to the WHO core prescribing indicators among prescribers at Request Muntanga First Level Hospital in the Southern Province of Zambia. The high usage of antibiotics is a serious public health issue and requires a multisectoral approach to address. To avoid the negative effects of prescribing antibiotics inappropriately, long-term interventional techniques are required. The amount of the prescribed injectables falls within the normal range. However, due to a large divergence from the WHO-recommended standards, this study indicated that polypharmacy, brand name use, and prescription medications from the Essential Medicines List were significant problems. There is a need to provide educational interventions to prescribers on the need to adhere to the WHO prescribing indicators and other recommended guidelines when prescribing medicines. Therefore, the Antimicrobial Resistance Coordinating Committee (AMRCC) must instigate AMS and surveillance programs to optimize the use of antimicrobials at the surveyed facility and in similar facilities across the country.

We are grateful to the Hospital Management at the Request Muntanga First Level Hospital in the Southern Province of Zambia for allowing us to collect data at the facility.

This study was supported by internal funding by the authors and is a part of our routine studies in the surveillance of antimicrobial use, resistance, and stewardship.