Pattern of medications causing adverse drug reactions and the predisposing risk factors among medical in-patients in clinical practice: A prospective study

Abstract

Background: Pharmacological interventions sometimes carry inherent significant risks which include adverse drug reactions (ADRs), drug interactions (DIs) and other consequences of inappropriate medication use. An adverse drug reaction (ADR) is defined in this study as a response to a drug which is noxious and unintended that occurs at doses normally used in man for therapeutic purposes. Despite the extensive study and attention given to ADRs, they still represent a clinically significant problem and burden with high incidence and prevalence. Aim: The main aim of this study was to evaluate and highlight the pattern of medications most frequently involved in ADRs and the predisposing risk factors among adult medical in-patients in clinical practice setting with the goal of preventing them and improving their treatment outcome. Methods: The patients admitted into the adult medical wards of a Nigerian University Teaching Hospital over a 9-month period from December 2013 to August 2014 were prospectively recruited for the study and followed up till discharge. Results: Five hundred and seven (507) patients were evaluated during the study, out of which 269 (53.1%) of them were males and 238 (46.9%) were females. The mean age of the study population was 48.9 ± 17.8 years (median of 46 years). The drugs most frequently involved in ADRs were insulin in 14 (27.5%) patients, Non-steroidal Anti-inflammatory drugs in 10 (19.6%) patients, antihypertensives in 8 (15.7%) patients, antimalarials in 5 (9.8%) patients, herbal medications in 4 (7.8%) patients and antibacterials in 3 (5.9%) patients. Furthermore, four (4) fatal ADRs were observed during the study; in which herbal medications caused two (2) deaths, sulfadoxine/pyrimethamine combination (maloxine®) caused one (1) death, and Iron dextran caused one (1) death. The most frequently affected body systems by ADRs were the central nervous system and the gastrointestinal system corresponding to the Antidiabetic drug-insulin use causing neuroglycopenic symptoms and Non-steroidal Anti-inflammatory drugs (NSAIDs) use causing NSAID-induced gastroenteritis/GIT bleeding, respectively. The elderly age group (≥ 65 years), presence of polypharmacy (taking more than 5 different pharmacologically active medications by a particular patient at the same time) and the presence of multiple comorbidities in a particular patient are clinically proven and significant risk factors found to be associated with and predisposed adult medical in-patients to ADRs in this study. Conclusion: The negative health burden and consequences of ADRs with the predisposing risk factors were significantly high among these adult medical in-patients. In this study, ADRs increase patients morbidity, mortality and length (duration) of hospitalization. Insulin and NSAIDs caused the highest number of ADRs which indicate that adequate caution, proper care and continuous monitoring must be implemented during the course of treating patients with these drugs in order to optimize their clinical efficacy and prevent the occurrence of ADRs in them.

Keywords

• Adult medical in-patients
• insulin
• non-steroidal anti-inflammatory drugs
• pattern of medications causing adverse drug reactions
• predisposing risk factors to adverse drug reactions