In pain studies, the double stopwatch (DSW) technique is used sometimes to assess onset of analgesia from oral analgesics. DSW measures time to first pain relief, confirmed by pressing a second stopwatch when a significant relief is reached. The applicability of DSW in evaluating sore throat is limited. Thus, Shephard A and colleagues in a pilot study evaluated the DSW technique for providing accurate information on time to onset of analgesia using flurbiprofen 8.75 mg lozenge in comparison to ibuprofen caplets in patients with sore throat.

This was a randomized, open-label, single-center study conducted on patients aged 16–65 and who had sore throat due to upper respiratory tract infection. Participants were given one flurbiprofen 8.75 mg lozenge (n=11) or two ibuprofen 200 mg caplets (n=12). Patients 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 recorded on a 100 mm visual analogue scale (VAS). The sore throat pain relief assessed using a 7-point rating scale at various time points 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 found to provide effectively better relief from sore throat pain. It was effective to reduce throat soreness and easing swallowing than ibuprofen at earlier time points, while ibuprofen was significantly better at later time points.

Therefore, it was concluded that DSW technique has the ability to assess onset of analgesia in sore throat for both systemic and locally delivered formats, but a broader study is required to confirm this finding.