Defining Optimal Dosing of Nimodipine in Aneurysmal Subarachnoid Hemorrhage: Study Protocol for a Systematic Review

Abstract Background: Nimodipine has been first line prophylaxis of cerebral vasospasm after subarachnoid hemorrhage for more than three decades, but its level of evidence has become controversial and essential questions regarding its pharmacological properties and its precise mechanism of action remain unclear. The level of evidence for Nimodipine was established in times when subarachnoid hemorrhage patients had their aneurysm secured in a delayed phase and when intravascular coiling was not established, these two clinical scenarios differ from current practice questioning the applicability of its therapeutic regimen. This review aims to investigate the strength of nimodipine as a prophylaxis for cerebral vasospasm within a contemporary context and to propose pathways for future research in nimodipine. Methods: We will search electronic databases including Medline, Embase, Cochrane, Web of Science and PubMed using a defined search strategy. Two authors will independently rate the quality of the searched evidence using the Chalmers scale for the scoring of studies ‘quality. Discrepancies will be assessed by a third independent author. All studies will be described in a table of studies’ characteristics and data extraction completed. Meta-analysis will be performed if there are two or greater homogeneous outcomes that suffices for reporting on measures of variability. Discussion: The results rising from this systematic review may guide further clinical trials focused on nimodipine dosing with the view of optimizing therapy for better neurological outcomes.Systematic review registration: PROSPERO ID = CRD42020188319