Intranasal Vasopressin Relieves Orthopedic Pain After Surgery.

Orthopedic pain after surgery is very common and difficult to manage. Although intranasal arginine vasopressin (AVP) relieves headache (tension-type headache and migraine mostly), the effect of intranasal AVP on the orthopedic pain after surgery is unknown. This study investigated the effect of intranasal AVP on orthopedic pain after surgery in a randomized controlled trial with a double-blind design. The study included 653 orthopedic patients and 661 health volunteers. Orthopedic pain was analyzed by the visual analogue scales (VAS) and AVP concentration was determined by radioimmunoassay. (1) intranasal AVP decreased the VAS level in orthopedic patients 2-4 weeks after surgery in a dose-dependent manner; (2) the cerebrospinal fluid (CSF) AVP concentration in orthopedic patients after surgery was higher than that in the health volunteers (38.57 ± 6.11 pg/mL vs 11.74 ± 2.85 pg/mL, p <.01), but had no change in plasma (p >.05); (3) CSF AVP concentration increased significantly in orthopedic patients during 24 hours after the intranasal AVP (p <.05 or.01), which related with VAS level negatively (all p <.01); (4) during 24 hours, intranasal AVP did not influence not only plasma AVP concentration, but also blood pressure, heart rate, respiratory rate and body temperature in orthopedic patients. The findings contribute valuable information that intranasal AVP can treat orthopedic pain after surgery, and AVP could be an option for pain relief by intranasal administration. • Arginine vasopressin (AVP) level in cerebrospinal fluid (CSF) of patients with orthopedic pain was higher than that in health volunteers. • Intranasal AVP relieved orthopedic pain in a dose-dependent manner. • Intranasal AVP increased CSF AVP level. • Blood pressure, heart rate, respiratory rate and body temperature did not change after intranasal AVP. • AVP could be an option for pain relief by intranasal administration.