ABSTRACT
A recently developed fast-release aspirin tablet formulation has been evaluated in two different pain models. The dental impaction pain model and the sore throat pain model are widely used for assessing analgesia, including acute mild-to-moderate pain. Both studies were double-blind, randomized, parallel group and compared a single dose of 1000 mg aspirin with 1000 mg paracetamol and with placebo and investigated the onset and overall time course of pain relief. Speed of onset was measured by the double-stopwatch method for time to meaningful pain relief and time to first perceptible pain relief. Pain intensity and pain relief were rated subjectively over a 6-h (dental pain) and 2-h (sore throat pain) time period. In both models fast-release aspirin and commercial paracetamol were statistically significantly different from placebo for onset of action, summed pain intensity differences and total pain relief. Meaningful pain relief was achieved within a median of 42.3 and 42.9 min for aspirin and paracetamol, respectively, in the dental pain model. The corresponding numbers in sore throat pain were 48.0 and 40.4 min. All treatments in both studies were safe and well tolerated. No serious adverse events were reported and no subject was discontinued due to an adverse event. Overall the two studies clearly demonstrated efficacy over placebo in the two pain models and a comparable efficacy and safety profile between aspirin and an equivalent dose of paracetamol under the conditions of acute dental pain and acute sore throat pain. Trial registration These trials were registered with ClinicalTrials.gov, registration number: NCT01420094, registration date: July 27, 2011 and registration number: NCT01453400, registration date: October 13, 2011.
