ABSTRACT
OBJECTIVE: To investigate the effect of intranasal oxytocin on chronic pelvic pain in a randomized, double-blind, within-subject crossover trial. Aims included: (1) determine intranasal oxytocin's effect on pain intensity and pain interference relative to placebo; (2) assess feasibility and acceptability. METHODS: Women with chronic pelvic pain were recruited from chronic pain and gynecology clinics between September 2017 and December 2018. Pain was recorded at pre-trial screening, and while administering intranasal oxytocin and placebo. Pain and pain-related interference were measured using the Brief Pain Inventory - Short Form. Feasibility and acceptability were measured using validated measures and interviews. RESULTS: Twenty-one women were randomized with sufficient data available from 12 to permit analyses. Relative to placebo, a 2-week course of oxytocin administration resulted in improvement in pain severity with no effect on pain-related interference. This effect was driven by four women who demonstrated a minimal clinically significant improvement in pain following intranasal oxytocin (no women met this threshold for placebo). Adherence to dosing was excellent and occurrence of adverse effects did not differ between oxytocin and placebo. CONCLUSION: Intranasal oxytocin may represent an adjuvant analgesic that could result in a minimal clinically significant improvement in pain among one in three women with chronic pelvic pain. Registration: ClinicalTrials.gov (Registration# NCT02888574).