BackgroundGlibenclamide has garnered attention due to its multifaceted neuroprotective effects in cases of acute central nervous system injury. We initiated a trial to explore the effectiveness and safety of a high dose of glibenclamide in the management of cerebral oedema following aneurysmal subarachnoid haemorrhage (aSAH).MethodsThis trial constituted a single-centre, randomised clinical study. Half of the 56 patients assigned to the glibenclamide group received 15 mg of glibenclamide tablets daily for 10 days (5 mg, three times/day). The primary outcome was the proportion of patients achieving the subarachnoid haemorrhage early brain oedema score dichotomy (defined as Subarachnoid Haemorrhage Early Brain Oedema Score 0-2) at the 10-day postmedication. The secondary outcome of cerebral oedema was the concentration of sulfonylurea receptor 1-transient receptor potential melastatin 4 (SUR1-TRPM4) in the plasma and cerebrospinal fluid.ResultsWe enrolled 56 patients diagnosed with aSAH, who were admitted to the neurosurgery intensive care unit between 22 August 2021 and 25 April 2023. The primary outcome revealed that the glibenclamide group exhibited a notably higher proportion of mild cerebral oedema in comparison to the placebo group (60.7% vs 42.9%, adjusted OR: 4.66, 95% CI 1.14 to 19.10, p=0.032). Furthermore, the concentration of SUR1-TRPM4 in the cerebrospinal fluid of the glibenclamide group was significantly higher than the placebo group (p=0.0002; p=0.026), while the plasma TRPM4 concentration in the glibenclamide group was significantly lower than the placebo group (p=0.001).ConclusionOral administration of high-dose glibenclamide notably reduced radiological assessment of cerebral oedema after 10 days of medication. Significant alterations were also observed in the concentration of SUR1-TRPM4 in plasma and cerebrospinal fluid. However, it is worth noting that glibenclamide was associated with a higher incidence of hypoglycaemia. Larger trials are warranted to evaluate the potential benefits of glibenclamide in mitigating swelling and then improving neurological function.Trial registration numberChiCTR2100049908.