Intranasal Vasopressin Relieves Orthopedic Pain After Surgery.

BACKGROUND: 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.

AIMS: This study investigated the effect of intranasal AVP on orthopedic pain after surgery in a randomized controlled trial with a double-blind design.

PARTICIPANTS: The study included 653 orthopedic patients and 661 health volunteers.

METHODS: Orthopedic pain was analyzed by the visual analogue scales (VAS) and AVP concentration was determined by radioimmunoassay.

RESULTS: (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.

COUCLUSIONS: 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.