Determinants of Adverse Drug Reactions in Patients With Breast Cancer Undergoing Treatment at Kenyatta National Hospital

Abstract

An adverse drug reaction is a harmful, unintended effect resulting from drug use at doses that are normally used for disease management. Cancer patients are prone to more adverse drug reactions due to the cytotoxic nature of chemotherapeutic agents and their effects on normal cells. To be able to treat patients with breast cancer effectively, healthcare providers should be able to predict and identify adverse reactions early enough to prevent and manage them accordingly. Objective: To evaluate the determinants of adverse drug reactions in patients with breast cancer undergoing treatment at Kenyatta National Hospital (KNH). Methodology: This was a cross-sectional study involving 139 participants selected using consecutive sampling. A researcher-administered questionnaire was used to collect data with supplementation from the medical records. The target population was adult breast cancer patients. The study population was adult breast cancer patients undergoing treatment at KNH. Descriptive and inferential analyses were used to summarize the continuous and categorical data at a 0.05 significance level using STATA version 15. Before the study, approval was sought from Kenyatta National Hospital -University of Nairobi Ethics and Research Committee (KNH/UoN-ERC), KNH department of research, and the National Commission for Science and Technology (NACOSTI). Results: One hundred and thirty-four participants (96.4%) had experienced at least one adverse drug reaction (ADR). The most prevalent ADR was neutropenia 94 (67.6%); most cases were grade 2 neutropenia 32 (34.0%). The mitigation strategies that were utilized most included drug holding (58,43%) and pre-chemotherapy anti-emetic 84 (84, 60.4%). The type of drug prescribed predicted the occurrence of several ADRs. Palbociclib was a strong predictor of neutropenia (p=0.017), and its severity (p=0.046) on bivariate analysis. It was also an independent predictor of anemia (p=0.027). Taxanes positively predicted the occurrence of anemia (p=0.045), alopecia (p=0.001), loss of appetite (p=0.042), and peripheral neuropathy (p=0.042). The use of an anthracycline similarly predicted the occurrence of alopecia (p=0.001), fatigue (p=0.016), and loss of appetite (p=0.002). Other predictors of ADRs in this patient population were the period since diagnosis, drug role, hypertension, diabetes mellitus, menopausal status, area of residence, chemotherapy cycles, duration of endocrine therapy and number of trastuzumab cycles. xviii Conclusion: The commonest drug regimen used for breast cancer treatment was Adriamycin/cyclophosphamide (AC) followed by Palbociclib-based regimens. Nearly all participants experienced at least one ADR, the commonest being neutropenia. Drug and non-drug strategies were utilized in the prevention and treatment of ADRs. Chemotherapy-induced nausea and vomiting (CINV) was not adequately mitigated through the use of pre- and post-chemotherapy medications as per current guidelines. The common significant ADR predictors across the ADRs identified were the type of drug used. Other factors that influence the development of ADRs were sociodemographic factors and clinical characteristics including comorbidity profile. Recommendations: Breast cancer patients undergoing treatment experience several ADRs. Policies that ensure the availability and affordability of the most frequently prescribed medications (adriamycin/cyclophosphamide, Palbociclib, and paclitaxel or docetaxel) should be developed or enhanced. Practices aimed at screening for ADR development, early detection, and prompt management should be strengthened. Further studies on the most prevalent ADRs such as neutropenia, anemia, alopecia, and CINV among other ADRs should be carried out. Relatively newer drugs including Palbociclib were utilized in large proportions in the management of breast cancer. A study that looks at the current treatment outcomes in this population should be carried out.