PLACEBO-CONTROLLED MODEL TO ASSAY THE ONSET OF ACTION OF NONPRESCRIPTION-STRENGTH ANALGESIC DRUGS

The definition and detection of the onset of analgesic drug activity r epresent two of the more complicated methodologic challenges in clinic al pharmacology. We addressed these issues by designing an analgesic a ssay with frequent posttreatment assessments to identify the first tim e when a subject experienced relief and when a nonprescription-strengt h analgesic could be distinguished from placebo. To test the feasibili ty of conducting this assay, 29 subjects with acute sore throat were r andomized to receive 200 mg ibuprofen, 400 mg ibuprofen, or placebo un der double-blind conditions. To identify the onset of analgesia, subje cts used three rating scales at 5-minute intervals over the first hour . Subjects completed each series of assessments efficiently, most with in 5 seconds. Each active agent was differentiated from placebo early after treatment (p less than or equal to 0.05), and there was dose-sep aration. We conclude that the sore throat pain model can be used to ev aluate the onset of action of nonprescription-strength analgesic agent s.