Drug-related problems (DRPs) encompass situations in which drug therapy may result in unintended or harmful outcomes including adverse effects, drug–drug interactions, cognitive impairment and metabolic problems (Garin et al. 2021). The risk for these negative health outcomes increases with the number of drugs also known as polypharmacy, which is defined as the concurrent use of five or more drugs (Garin et al. 2021). Together with an increase in life expectancy, polypharmacy has been found to reach up to 90% in adults over 75 years of age (Garin et al. 2021). During hospital admission, adding new medicines for acute health problems may exacerbate the risk of developing DRPs, which can result in potential life-threatening consequences for patients, increased hospital stay and healthcare costs (Abunahlah et al. 2018; Garin et al. 2021; Hoel, Connolly & Takahashi 2021).

The World Health Organization (WHO) has cited DRPs as the leading cause of death in the United States (Ni et al. 2021; WHO 2016). The prevalence of DRPs proves to be a global challenge, as several studies identified DRPs from various countries globally, including those in Africa. The most identified DRPs globally are adverse drug events (ADE) and drug–drug interactions as indicated by Garin et al. (2021), Abunahlah et al. (2018), Annor, Schellack and Gous (2014), Abdel-Latif and Abdel-Wahab (2015), Lenssen et al. (2016) and Sungsana et al. (2023).

Drug-related problems can be defined as any event that occurs during drug therapy, for any indication that can alter the health outcomes or result in undesired outcomes for the patient (Abunahlah et al. 2018; Zaal et al. 2013). The Pharmaceutical Care Network Europe Association (PCNE) developed a classification system to categorise DRPs into four categories, such as Indication, Effectiveness, Drug safety and Drug use (Zaal et al. 2013). The examples of these categories are patients experiencing pain and not receiving pain medication or receiving medicine dosages that are too high [causing toxicity] or too low [causing inefficacy] (Zaal et al. 2013).

Contributing factors to DRPs can stem from errors made during prescribing, dispensing or the administration of medicine. Errors such as the prescriber selecting the wrong medicine or dose, the pharmacist dispensing the wrong medicine or wrong strength or the medicine being administered at the wrong frequency can cause DRPs (Abunahlah et al. 2018; Pharmaceutical Care Network Europe 2019; Pokkuluri et al. 2023). These factors could be prevented by the involvement of the clinical pharmacist as part of the multidisciplinary team, promoting rational drug use and enhancing drug safety and effectiveness (Ahmed et al. 2021; Chevalier et al. 2016; Movva et al. 2015; Pokkuluri et al. 2023). Clinical pharmacists are specially trained professionals who apply knowledge of pharmacology, toxicology, pharmacokinetics and pharmacotherapeutic to optimise drug therapy and provide comprehensive pharmaceutical care, ultimately improving patients’ quality of life (American College of Clinical Pharmacy 2016; Bronkhorst, Schellack & Gous 2022).

The incorporation of clinical pharmacists into multidisciplinary teams has been shown to increase the detection of DRPs according to research (Albayrak & Özbalcı 2024). Interventions described in research studies focusing on DRPs are varied and cover a broad range of aspects, such as medication reconciliation, medication adherence, dose adjustment or therapeutic indication (Garin et al. 2021). Recent international clinical pharmacy forums, including the 50th ESCP symposium, further highlight that managing polypharmacy and ensuring medication safety require highly individualised, interprofessional and person-centred approaches (Dreischulte et al. 2022b).

Clinical pharmacists contribute directly to such approaches through their pharmacotherapy expertise to support multidisciplinary healthcare teams, working to improve how medicines are used in order to meet both patient-centred and broader public health objectives (Dreischulte et al. 2022a).

Clinical pharmacists, through application of pharmaceutical care, can ensure rational drug use by choosing the most appropriate medication, dose and frequency, to ensure cost-effective therapy that ensures safe and effective use of medication, to minimise DRPs (Albayrak & Özbalcı 2024; Bronkhorst et al. 2022; Chauhan et al. 2018; Harikrishna 2021; Mateti et al. 2014).

Through the involvement of a clinical pharmacist in the multidisciplinary healthcare team, the study aimed to identify and analyse DRPs. As a result of the identification of DRPs, the study then aimed to explore and describe the role that clinical pharmacists play in healthcare teams to minimise DRPs.

This descriptive, quantitative study included n = 181 patient file reviews with the aim to identify and classify DRPs and to show the role clinical pharmacists can play as part of the multidisciplinary healthcare team to minimise DRPs.

Patient files for n = 181 patients who met the inclusion criteria were reviewed. Two-thirds of the participants were male, with a median age of 44 years. This is contrary to the country’s demographics of 48% males with a median age of 28 years (Statisticstimes.com – South Africa demographics 2024). Comorbidities identified in the population were mostly hypertension, HIV/AIDS and diabetes, which is consistent with the quadruple burden of disease identified in South Africa (WHO 2018) - Refer to Appendix 1: Figure 1-A1. Most of the patients (especially the age group 41–60 years) had two or more comorbidities and were prescribed polypharmacy regimens consisting of more than five medications. These patterns are consistent with global observations on polypharmacy in populations with multiple comorbidities, also described during the 50^th ESCP symposium (Dreischulte et al. 2022a). This also aligns with the findings of Farrell, Szeto and Shamji (2011), who found that polypharmacy is common among older adults, with patients receiving 8 to 13 prescribed medications and experiencing an average of 2 to 3 DRPs. One of the assumed reasons for this trend in this study was complex comorbidities seen in this group of patients (Farrell et al. 2011).

Notwithstanding the fact that polypharmacy was present in more than 60% of the study population, no statistical significance (p = 0.089) was identified between polypharmacy and DRPs. This diverges from findings that found polypharmacy as the cause of high DRP prevalence, even in other African countries (Buda et al. 2021; Mamo & Alemu 2020; Mekonnen, Ayalew & Tegegn 2021). However, the study still found a high incidence of DRPs (241 with an average of 1.76 per patient). Studies performed in internal medicine wards in both developed and developing countries have shown similar results of between 1.3 and 2.6 DRPs per patient (Adhikari et al. 2021; Guignard et al. 2015; Pokkuluri et al. 2023). Additionally, the majority of these DRPs are in the age group of 41–60 years (Pokkuluri et al. 2023; Shareef, Sandeep & Shastry 2014). It was further speculated that increased DRPs may be the result of increased comorbidities and polypharmacy (Pokkuluri et al. 2023). The influence of comorbidities and polypharmacy on DRPs was demonstrated by a study conducted in the elderly that showed that elderly patients had a higher chance of developing DRPs because of the high number of comorbidities and drugs prescribed in this population (Hailu et al. 2020).

In this study, which was carried out in a developing country, failure to receive therapy (under-administration or drug not administered at all) was the highest reported DRP, which does not correlate to polypharmacy at all but rather with systemic challenges. In developing countries, non-administration of medication was cited for around 21% of DRPs (Abunahlah et al. 2018; Leite et al. 2016). This is in contrast with developed countries who reported drug–drug interactions (35% – 48%) as the largest contributor to DRPs (Lenssen et al. 2016; Mohammed et al. 2017; Pokkuluri et al. 2023). Factors such as shortage of nursing staff, high workload, few clinical pharmacists, limited resources and a weak medication dispensing system are some contributors identified to lead to incidences of non-administration of medication (Abrahams, Thani & Kahn 2022; Keers et al. 2018; Leite et al. 2016). Similarly, the South African Nursing Council (SANC) recognises that the ratio of nurses to patients indicates short staffing at 1:213 in South Africa (Abrahams et al. 2022).

Furthermore, drug identification using the ATC classification system showed that central nervous system drugs were most frequently involved in DRPs, accounting for 136 cases (26.3%). Paracetamol was most frequently linked to missed doses, therapeutic duplication and overdose – likely because of its widespread use for pain management, which may lead to overprescription. The practice of prescribing paracetamol ‘as needed, or PRN’ was not regarded as a missed dose. A similar approach was taken in cases where a nurse indicated on the prescription that the patient refused medication or was vomiting in the context of oral dosage formulations. Results from other studies reported on paracetamol in terms of overdose or therapeutic duplication, rather than missed doses (Guignard et al. 2015). Although anti-infectives were not the highest contributors to DRPs in this study, the number of DRPs caused by these drugs was 130 (25.2%), making it the second highest drugs to contribute to DRPs. In recent studies, the anti-infective for systemic use, especially antimicrobials, were reported as the class that contributed the most to DRPs, especially because of dosing (over or underdosing) and treatment duration issues (Adhikari et al. 2021; Pokkuluri et al. 2023).

In this study, the clinical pharmacist used the PCNE system to identify and classify DRPs and made 277 recommendations to other members of the multidisciplinary healthcare team. To address missed medication doses, the clinical pharmacist reminded nurses to ensure all medications were administered as prescribed. Most recommendations to prescribers involved adding omitted treatments, particularly antiretroviral or antituberculosis drugs.

Recommendations to discontinue a drug or request culture and sensitivity tests were more likely to be accepted by the doctor. The method of communicating the recommendation may have influenced the acceptance rate of recommendations. When direct verbal communication was used to make recommendations, the acceptance rate was higher than when messages were written in the patient’s clinical notes, where prescribers were not available for communication. Evidence for successful verbal communication was shown by pharmacotherapy experts, in a study where they participated in medical rounds with prescribers, communicating directly to achieve an acceptance rate of 84% (Guignard et al. 2015). In several studies, the presence of clinical pharmacists at ward level has resulted in positive change by reducing DRPs, which is observed by other healthcare professionals (Ahmed et al. 2021; Chevalier et al. 2016; Movva et al. 2015; Pokkuluri et al. 2023).

The study highlighted the clinical pharmacist’s capability to recognise and classify DRPs in hospitalised patients. The DRPs in this study ranged in severity from omitted doses to therapeutic duplication and drug–drug interactions. The incidence of DRPs increased with higher comorbidities and age. The inclusion of a clinical pharmacist within the multidisciplinary team could play a significant role in reducing the incidence of DRPs in hospitalised patients.