We aimed to characterize non-oncologic chronic drug therapy of bladder cancer (BC) patients and evaluate a possible impact on recurrence-free (RFS) and cancer-specific survival (CSS). Patients with a first diagnosis (FD) of BC or radical cystectomy (RC) were included in a prospective, monocentric, observational study. Drugs and medical data was assessed at start and three-monthly for 24 months. Drugs were classified by anatomical-therapeutic-chemical code (ATC). Endpoints for outcome analysis were RFS and CSS in univariate (Kaplan–Meier curves and log-rank test, Cox regression for Hazard Ratio (HR)) and multivariate (Cox regression models) analyses. Of 113 patients, 52 had FD and 78 RC. Median age was 74 and 72 years, 83% and 82% were male. Drugs of 114 ATC classes were taken by 48 (92%) FD patients (median number 4.5/IQR 2–7.5) and 73 (94%) of RC patients (median 5/IQR 2–9). In univariate analysis (log-rank test (p)/Cox regression (HR, 95% CI, p)), polypharmacy (p = 0.036/HR = 2.83, 95% CI = 1.02–7.90, p = 0.047), calcium channel blockers (p = 0.046/HR = 2.47, 95% CI = 0.97–6.27, p = 0.057) and proton pump inhibitors (p = 0.015/HR = 3.16, 95% CI = 1.18–8.41, p = 0.022) had a significant negative impact on RFS in RC patients, statins (p = 0.025/HR = 0.14, 95% CI = 0.02–1.06, p = 0.057) a positive effect on RFS in FD patients, angiotensin-converting enzyme inhibitors (p = 0.008/HR = 10.74, 95% CI = 1.20–96.17, p = 0.034) and magnesium (p = 0.042/HR = 5.28, 95% CI = 0.88–31.59, p = 0.067) a negative impact on CSS in FD patients. In multivariate analysis, the only significant drug effects were the negative impact of angiotensin-converting enzyme inhibitors (HR = 15.20, 95% CI = 1.30–177.67, p = 0.030) and magnesium (HR = 22.87, 95% CI = 1.57–333.81), p = 0.022) on CSS in FD patients, and the positive impact of statins (HR = 0.12, 95% CI = 0.01–0.97, p = 0.047) on RFS in FD patients. Impact of non-oncologic drugs on RFS and CSS was small in this prospective study. Thus, appropriate treatment of comorbidities is encouraged.