Nimodipine differs from the currently used calcium channel blockers in its increased lipophilicity and cerebrovascular selectivity. Meta analysis of 7 clinical trials indicate that nimodipine is effective in improving outcomes (although not necessarily mortality) due to cerebral artery spasm and subsequent neurologic deficits in patients with subarachnoid hemorrhage (SAH) and ruptured cerebral aneurysms [209]. Despite clinical benefit from nimodipine on neurologic status, no firm radiographic data exists to show that prevention or relief of vasospasm is in fact the mechanism of action of nimodipine in SAH [210].