Patterns of Furosemide Use and Associated Adverse Drug Events in Primary Healthcare Settings: A Retrospective Pharmacoepidemiological Study

Background: Furosemide is one of the most frequently prescribed loop diuretics for cardiovascular conditions, particularly in the management of volume overload and acute elevations in blood pressure. However, detailed real-world data describing its utilization characteristics and documented safety outcomes in primary healthcare settings remain limited, especially in underrepresented health systems. Objective: This study aimed to describe real-world patterns of furosemide utilization, including indications and concomitant treatment patterns, and to document associated adverse drug events and short-term clinical outcomes in routine primary healthcare practice. Methods: A retrospective pharmacoepidemiological observational study was conducted between January and December 2025 in a primary healthcare center. Medical records of 1300 adult patients who received furosemide for cardiovascular indications were reviewed. Indications included arterial hypertension, hypertensive crises, and conditions related to volume overload. Utilization characteristics were operationalized as indication distribution, monotherapy versus combination therapy, and recurrence patterns within the study period. Data collected included demographic characteristics, primary and comorbid diagnoses, blood pressure values recorded before and after administration, furosemide dose and route of administration, concomitant antihypertensive therapy, documented adverse drug events as recorded in routine clinical documentation, recurrent presentations related to hypertensive crises, and the need for hospital referral. Descriptive statistics and paired comparative analyses were performed, with statistical significance set at p < 0.05. Results: The mean patient age was 62.4 ± 11.8 years, with a male predominance (54.1%). Arterial hypertension was the most frequent recorded indication (78.6%), while 32.4% of patients had multiple cardiovascular diagnoses. A statistically significant reduction in systolic blood pressure (from 176.3 ± 18.5 mmHg to 148.7 ± 16.2 mmHg, p < 0.001) and diastolic blood pressure (from 101.2 ± 11.4 mmHg to 89.6 ± 9.8 mmHg, p < 0.001) was observed between measurements recorded before and after administration during the same clinical episode. Recurrent presentations related to hypertensive crises were documented in 27.9% of patients during the study period. Adverse drug events were documented in 9.6% of cases, most commonly dehydration and suspected electrolyte disturbances as noted in routine clinical records. Hospital referral was required in 6.8% of patients. Conclusions: In this real-world primary healthcare cohort, furosemide was commonly used across a heterogeneous mix of cardiovascular indications, predominantly in combination with other antihypertensive agents. Observed temporal reductions in blood pressure and documented adverse events reflect routine clinical practice rather than controlled treatment effects. These findings provide descriptive pharmacoepidemiological evidence from a primary care setting and underscore the importance of careful monitoring, documentation, and rational prescribing in patients receiving loop diuretics.