Current Therapeutic Drugs Against Cerebral Vasospasm after Subarachnoid Hemorrhage: A Comprehensive Review of Basic and Clinical Studies

Background: Cerebral vasospasm (CVS) is well known as a major complication in subarachnoid hemorrhage (SAH) patients, and research has long been focused on improving morbidity and mortality. As CVS commonly develops from day 4 to day 14 after SAH onset, SAH patients require therapies with drugs for preventing CVS after surgical treatment for the source of hemorrhage, mostly ruptured intracranial aneurysms. It is thought that the pathogenesis of CVS is initiated by prolonged smooth muscle contraction, and the subsequent hypoperfusion and cytotoxic responses induce cerebral ischemia. Although therapeutic investigations have historically focused on morphological improvement, the improvement of outcome is limited by the reversal of arterial narrowing. Therefore, it might be important to look back at evidence from long-lasting studies of CVS and to determine a highroad to effective drugs, including combination therapy. Objective: In this review, we introduce current candidate beneficial drugs against CVS in clinical SAH, including nimodipine and other Ca2+ channel antagonists, magnesium sulfate, clazosentan, statins, cilostazol, eicosapentaenoic acid, fasudil hydrochloride, milrinone, and edaravone, all of which have been frequently studied in recent years.