A double-blind, single-dose parallel study was conducted to assess refinements of a previously tested model for evaluating treatment of sore throat pain. Patients with tonsillopharyngitis randomly received either 400 mg ibuprofen (n = 39), 1000 mg acetaminophen (n = 40), or placebo (n = 41). At hourly intervals for 6 hours the patients reported pain intensity and pain relief on conventional scales and two sensory qualities of throat pain ("swollen throat" and "difficulty swallowing") on two new visual analog scales. Both active agents were significantly more effective than placebo for all efficacy measurements (p less than 0.01). Ibuprofen, 400 mg, was more effective than acetaminophen, 1000 mg, on all rating scales, conventional and new, at all time points after 2 hours and overall (p less than 0.01). There were no side effects. We conclude that sore throat is a pain model that can be used to discriminate between active medication and placebo, as well as between two effective over-the-counter analgesics.

A new onset-of-action model was utilized to distinguish the pharmacologic activity of flurbiprofen 8.75mg delivered in a lozenge from the demulcent effect of the lozenge base. In a randomized, double-blind, placebo-controlled trial, patients with sore throat rated pain on a Sore Throat Pain Intensity Scale before taking one flurbiprofen or placebo lozenge and at frequent (2-minute) intervals over the first hour after treatment. Further ratings of the Sore Throat Pain Intensity Scale and other patient-reported outcomes (difficulty swallowing, swollen throat, pain relief) were obtained at varying intervals over 6 hours. Onset of pharmacologic activity was defined as the median time of first perceived pain reduction if a patient reported clinically meaningful (at least moderate) relief. The conventional method of comparing mean treatment responses at each time point was also implemented. Demulcent action was detected at the first 2-minute assessment. By the new method, 102 flurbiprofen-treated patients were identified as first perceiving pain relief at 12 minutes, compared with >120 minutes by 102 patients using placebo (P<0.001). By the conventional method, mean percentage pain reduction for flurbiprofen 8.75 mg was first significantly differentiated from placebo at 26 minutes (P<0.05). Efficacy of flurbiprofen lozenge was demonstrated for 3.5-4hours on the 4 patient-reported outcomes (all P<0.05 compared with placebo). There were no serious adverse events. This patient-centered onset-of-action model identifies the initiation of pain relief in patients who are definite drug responders, here demonstrating that a flurbiprofen 8.75-mg lozenge provides early relief of sore throat.

Clinical Pharmacology and Therapeutics (1984) 36, 151–156; doi:

To determine the relative analgesic efficacy of ibuprofen 400 mg and acetaminophen 1000 mg, we conducted a single-dose, double-blind, placebo-controlled, randomized clinical trial using a standard assay for analgesic agents, the dental pain model. At regular intervals over 6 hours, 184 patients who had undergone dental impaction surgery rated pain intensity and relief on categorical scales and pain half-gone on a dichotomous nominal scale; a categorical overall evaluation was completed at the end of 6 hours. Both active agents were effective compared to placebo. Ibuprofen 400 mg was more effective than acetaminophen 1000 mg for Sum Pain Intensity Difference (SPID), Total Pain Relief (TOTPAR), sum pain half-gone, and overall evaluation (P less than .05 to P less than .001). The time-effect curves demonstrated a greater peak effect and longer duration of action for ibuprofen 400 mg compared to acetaminophen 1000 mg. Side effects were reported in five ibuprofen patients, 11 acetaminophen-treated patients, and seven placebo patients. Based on the results of this clinical study, we conclude that ibuprofen 400 mg is a safe and more effective analgesic than acetaminophen 1000 mg for patients with acute pain.