Polypharmacy and Drug–Drug Interactions in Hospitalized Hypertensive Patients in Mozambique: A Cross-Sectional Study

Introduction: Hypertension affects approximately 25.3% of Mozambican adults, representing a primary driver of cardiovascular morbidity. Despite its high prevalence, granular clinical data detailing the safety and complexity of inpatient pharmacotherapy in sub-Saharan acute care settings remain critically scarce.

Objective: To characterize the inpatient pharmacotherapeutic profile, quantify the prevalence and severity of potential drug–drug interactions (DDIs), and describe the distribution of drug-related problems (DRPs) among hypertensive patients admitted to a quaternary referral hospital in Mozambique.

Methods: An observational, cross-sectional, exploratory study was conducted in the Internal Medicine wards of Nampula Central Hospital (NCH) over a two-month period (December 2025–January 2026). Seventy-one patients hospitalized for 3 consecutive days were enrolled using convenience sampling. Clinical data were obtained via structured patient interviews and electronic/physical medical records. Potential DDIs were screened using the Medscape Drug Interaction Checker and stratified by clinical severity. Statistical analysis relied on non-parametric tests, with precision reported via 95% confidence intervals (CIs).

Results: The cohort was predominantly female (56.3%) and elderly (60–69 years: 25.4%). A heavy burden of cardiorenal multimorbidity was present, led by heart failure (36.6%) and chronic kidney disease (32.4%). Inpatient medication burden was severe: patients received a median of 7 drugs (IQR: 6–8.5; range: 3–12), with systemic hospital polypharmacy (5 drugs) reaching 91.5% (95% CI: 82.8–96.1). Concurrently, potential DDIs and overall DRPs were near-universal, affecting 84.5% (95% CI: 74.3–91.1) and 90.1% (95% CI: 81.0–95.1) of the cohort, respectively. Out of 245 potential DDIs identified, 64.1% were of major clinical severity, dominated by the furosemide–lisinopril pair (16.3%). Because DRPs affected nearly all participants, statistical determinants could not be contrastingly isolated. Nevertheless, inpatient protocols achieved a significant reduction in mean blood pressure (systolic: -38.9 mmHg; diastolic: -18.1 mmHg; both p < 0.001), establishing a 59.2% control rate (<140/90 mmHg) at interview.

Conclusion: Although acute inpatient management successfully controls peripheral blood pressure, these complex cardiorenal patients carry an extreme medication burden characterized by near-universal DRPs and high-severity potential DDIs. These findings underscore that in-hospital hypertension care in resource-limited wards is fundamentally a medication safety challenge, reinforcing the urgent need to integrate clinical pharmacists into multidisciplinary ward teams to conduct systematic, proactive pharmacological surveillance.