Bisoprolol and Amlodipine Co-Administration with Glimepiride in a Diabetic Rat Model: A Statistical and Machine Learning Analysis

Background/Objectives: Diabetes mellitus type 2 (T2DM) is often associated with hypertension, necessitating treatment with combinations of medications that address both glycemic control and blood pressure. Whether commonly co-prescribed antihypertensives modify the glycemic efficacy of a sulfonylurea remains insufficiently characterized in controlled preclinical models. Methods: One hundred adult male Wistar rats were allocated to ten parallel groups (n = 10): healthy and diabetic untreated controls; glimepiride, bisoprolol or amlodipine monotherapy (in healthy and diabetic animals); and the diabetic combinations glimepiride+bisoprolol and glimepiride+amlodipine. T2DM was induced with a high-fat diet plus low-dose streptozotocin (35 mg/kg, i.p.) and confirmed by fasting blood glucose ≥ 200 mg/dL. Glycated hemoglobin (HbA1c) was measured weekly for 11 weeks. Non-parametric inference (Kruskal–Wallis, Dunn’s with Bonferroni correction, Mann–Whitney U, Wilcoxon signed-rank) was complemented by Random Forest regression and PCA/K-means clustering. Results: Week-11 HbA1c differed markedly across groups (Kruskal–Wallis H = 94.3, p < 0.001). Glimepiride + bisoprolol achieved near-normal control (4.37% ± 0.15), statistically indistinguishable from healthy groups (p ≥ 0.33), and was the only diabetic regimen with a declining trajectory (−0.66 percentage points; Wilcoxon p = 0.004). Adding either antihypertensive to glimepiride did not worsen glycemic control. Amlodipine monotherapy did not attenuate hyperglycemia (8.47% ± 0.20), approaching that of untreated diabetic controls (9.31% ± 0.18), consistent with the absence of intrinsic glucose-lowering activity. All agents showed pronounced disease-state dependence (healthy–diabetic divergence 2.33–3.13 points). Random Forest prediction was accurate (R2 = 0.985), and unsupervised clustering separated effective from ineffective regimens, corroborating the statistical findings. Conclusions: In this model, bisoprolol co-administration enhanced and amlodipine co-administration preserved glimepiride-mediated glycemic control. Glimepiride+bisoprolol emerged as the most effective regimen, supporting cardioselective β-blockade as a metabolically favorable antihypertensive partner for sulfonylurea therapy and warranting clinical confirmation. More broadly, these results provide a preclinical, evidence-based rationale for selecting metabolically favorable antihypertensives in patients with coexisting T2DM and hypertension, with the potential to improve glycemic outcomes and reduce the risk of adverse drug–disease interactions during combination therapy.