A Pilot Study to Evaluate the Double Stopwatch Technique for Determining Onset of Sore Throat Pain Relief by a Lozenge

Abstract

In pain studies, onset of analgesia from oral analgesics is sometimes assessed using the double stopwatch (DSW) technique, which measures time to first pain relief, confirmed by pressing a second stopwatch when meaningful relief is reached. Its applicability in evaluating sore throat is limited. This pilot study evaluates the DSW technique for providing accurate information on time to onset of analgesia using flurbiprofen 8.75 mg lozenge compared with ibuprofen caplets in patients with sore throat. A randomised, open-label, single-centre study was conducted in subjects aged 16–65 years with sore throat from upper respiratory tract infection. Subjects received one flurbiprofen 8.75 mg lozenge (n=11) or two ibuprofen 200 mg caplets (n=12). Subjects recorded time to first perceptible sore throat pain relief by stopping the first stopwatch and time to meaningful relief (first confirmed perceptible pain relief) by stopping the second stopwatch. Throat soreness and difficulty swallowing were assessed on a 100 mm visual analogue scale, and sore throat pain relief assessed using a 7-point rating scale at various timepoints post-dose. The Kaplan–Meier median time to first confirmed perceptible pain relief was 7.2 minutes (95% CI 2.6, 22.6) for flurbiprofen lozenge and 18.0 minutes (95% CI 16.0, indeterminate) for ibuprofen (p=0.12). The time to first unconfirmed perceptible sore throat pain relief of 4.1 minutes (95% CI 1.1, 7.2) was significantly shorter for flurbiprofen lozenge compared with 17.6 minutes (95% CI 16.0, 22.9) for ibuprofen (p=0.003). Flurbiprofen lozenge was significantly better at relieving sore throat pain, reducing throat soreness and easing swallowing than ibuprofen at earlier timepoints, while ibuprofen was significantly better at later timepoints. The DSW technique has the potential to assess onset of analgesia in sore throat for both systemic and locally delivered formats, but a larger study is required to confirm this.