A Comparison Between Enteral and Intravenous Nimodipine in Subarachnoid Hemorrhage: A Systematic Review and Network Meta-Analysis

Our objective was to compare the effectiveness of intravenous and enteral nimodipine in preventing poor outcome from delayed cerebral ischemia in patients with subarachnoid hemorrhage. We performed a systematic search and a network meta-analysis using the following databases: PubMed, Scopus, the Cochrane Central Register of Controlled Trials, and Google Scholar. Risk of Bias 2 tool was used to assess risk of bias of included studies. A ranking among methods was performed on the basis of the frequentist analog of the surface under the cumulative ranking curve. Published studies that met the following population, intervention, comparison, outcomes and study (PICOS) criteria were included: patients with subarachnoid hemorrhage aged 15 years or older (P); nimodipine, intravenous and oral formulation (I); placebo or no intervention (C); poor outcome measured at 3 months (defined as death, vegetative state, or severe disability), case fatality at 3 months, delayed cerebral ischemia, delayed ischaemic neurologic deficit, and vasospasm measured with transcranial Doppler or digital subtraction angiography (O); and randomized controlled trials (S). No language or publication date restrictions were applied. Ten studies were finally included, with a total of 1527 randomly assigned patients. Oral and intravenous nimodipine were both effective in preventing poor outcome, delayed cerebral ischemia, and delayed ischaemic neurological deficit. Neither treatment was effective in improving case fatality. Evolving clinical protocols over a 30-year period and the risk of bias of the included studies may limit the strength of our results. Enteral and intravenous nimodipine may have a similar effectiveness in terms of preventing poor outcome, delayed cerebral ischemia, and delayed ischaemic neurological deficit. More research may be needed to fully establish the role of intravenous nimodipine in current clinical practice.