Safety of Adult-dose Clazosentan in an Adolescent with Aneurysmal Subarachnoid Hemorrhage: A Case Report

Aneurysmal subarachnoid hemorrhage is extremely rare in children, and treatments for postoperative cerebral vasospasm and delayed cerebral ischemia have not yet been established. Clazosentan is a selective endothelin A receptor antagonist that inhibits symptomatic cerebral vasospasm onset in adults with aneurysmal subarachnoid hemorrhage. However, its administration in children is notably limited. This case report demonstrates the safety of clazosentan in early adolescent patients with aneurysmal subarachnoid hemorrhage. A 14-year-old male presented with a subarachnoid hemorrhage and intracerebral hematoma due to a ruptured saccular aneurysm at the right internal carotid artery terminus. After clipping and hematoma removal, clazosentan was administered at 10 mg/h (0.18 mg/kg/h) for 14 days from postoperative day 1 according to the adult dose. Clinical examination as well as postoperative magnetic resonance imaging and computed tomography angiography did not reveal a cerebral vasospasm or cerebral infarction. No adverse events such as hypotension, pulmonary edema, or cerebral edema were observed during the administration period. Thirty days after surgery, the patient was discharged with a modified Rankin Scale score of 1. This is the first study to demonstrate that an adult dose of clazosentan is safe for adolescent aneurysmal subarachnoid hemorrhage. This report suggests the potential clinical application of clazosentan in adolescents but does not indicate efficacy, and further studies involving additional cases are needed.