5-Aminolevulinic
acid (5-ALA) is used for the photodynamic diagnosis of malignant
tumors and has been effectively utilized to improve the complete resection rate and reduce the risk of
tumor recurrence. However, intraoperative
hypotension is a common adverse effect of oral 5-ALA, and it occasionally progresses to severe prolonged
hypotension requiring high-dose
catecholamine administration. We report a case of intraoperative
hypotension due to oral 5-ALA in which
arginine vasopressin (AVP) administration was effective for increasing the blood pressure. A 77-year-old man scheduled for a
craniotomy for
glioma was administered 5-ALA orally before surgery. After the induction of
anesthesia, his blood pressure decreased substantially. Although we administered various
vasopressor agents,
hypotension was prolonged. However, after starting a continuous administration of AVP, the systolic blood pressure increased, and the hemodynamic parameters remained stable during the remainder of the operation. 5-ALA administration may lower blood pressure by inducing
nitric oxide production, and AVP inhibits
inducible nitric oxide synthase messenger RNA expression and interleukin-1β-stimulated
nitric oxide production. In light of these mechanisms, AVP may be a reasonable treatment agent for
hypotension induced by 5-ALA.