Glioblastomas are malignant brain tumors with poor prognosis. Lately, data from clinical studies assessing the role of co-medications in different cancer types suggested reduced mortality and potential anti-tumor activity for statins, angiotensin-I converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (sartans). Here, we analysed the association of co-treatment with statins, ACEI or sartans with outcome in a cohort of 810 patients enrolled in the phase III CENTRIC and phase II CORE trials on the role of the integrin antagonist, cilengitide, in newly diagnosed glioblastoma with or without O6-methylguanine DNA methyltransferase (MGMT) promoter methylation. Progression-free survival (PFS) and overall survival (OS) were analysed for each medication in the pooled patient group. No association was found for co-medication with either drug for PFS or OS. Median OS was 22.1 (statins) versus 22.2 (control) months (HR 1.06, 95% CI 0.81–1.39, p = 0.69), 20.4 (ACEI) versus 22.6 (control) months (HR 1.25, 95% CI 0.96–1.62, p = 0.10), and 21.7 (sartans) versus 22.3 (control) months (HR 0.86, 95% CI 0.61–1.21, p = 0.38). None of the comparisons showed a signal for different PFS or OS when analyses were controlled for MGMT promoter methylation or treatment group (TMZ/RT → TMZ vs. RT + CIL + TMZ → TMZ + CIL). This secondary analysis of two large glioblastoma trials thus was unable to detect evidence for an association of the use of statins, ACEI or sartans with outcome in patients with newly diagnosed glioblastoma. These data challenge the rationale for prospective studies on the possible role of these non-tumor-specific drugs within the concept of drug repurposing.