Soluble epoxide hydrolase (sEH) is the metabolizing enzyme of epoxyeicosatrienoic acids (EETs), which may play a role in reducing neuroinflammation and regulating cerebral blood flow after subarachnoid hemorrhage (SAH). Hypotheses: Pharmacologic inhibition of the sEH enzyme is safe and will result in increased EETs availability in the blood and cerebrospinal fluid. This study is a double-blind, placebo-controlled, phase 1b randomized trial to evaluate the safety and efficacy of GSK2256294, a novel soluble epoxide hydrolase inhibitor in patients with aneurysmal SAH.