: Neck-specific exercise (NSE), administered by a physiotherapist or via e-health platforms (NSEIT), has demonstrated promising outcomes in individuals with chronic whiplash-associated disorders (WAD). Whether NSE and NSEIT lead to changes in analgesic use is of clinical importance, but remains unknown. This study aimed to investigate the changes in analgesic use among participants with WAD following either NSE or NSEIT.

: A multicentre randomised controlled noninferiority trial with masked assessors was conducted across multiple physiotherapy clinics. Participants (n = 140) between 18 and 63 years of age with WAD grade II or III were randomised to 2 groups (n = 70, each) for a 12-week physiotherapist-guided NSE or NSEIT. Data on analgesic use were collected via self-reported questionnaires with predefined categories at baseline, and after 3 and 15 months.

: In the NSE group, analgesic use decreased significantly at the 3-month follow-up ( P  = 0.009; Cohen’s d = 0.34) but returned to baseline by the 15-month follow-up. In the NSEIT group, analgesic use continued to decline and was significantly reduced at the 15-month follow-up ( P  = 0.018; Cohen’s d = 0.33). Daily analgesic use remained stable in both groups throughout the follow-up period. A significant reduction ( P ≤0.022) in occasional analgesic use was observed in the NSEIT group, with a large effect size for Cohen’s g (0.35∼0.5) and a moderate effect size for r (0.33∼0.43).

: Fewer participants with WAD II or III continued using analgesics following the intervention (NSE or NSEIT). The reduction in analgesic use followed a more sustained pattern in the NSEIT group; however, no statistically significant between-group differences were found at either follow-up, indicating broadly comparable benefits of both interventions. The additional reduction in occasional analgesic use in the NSEIT group suggests a potentially meaningful clinical trend that merits confirmation in adequately powered trials.

Trial registration: ClinicalTrials.gov (NCT03022812).