Drug-Test Interaction in the Submaximum-Effort Tourniquet Technique 1 2

Summary

A double-blind crossover comparison of flufenisal and aspirin was made using the submaximum-effort tourniquet technique to test analgesic effect. Each of 10 men was tested at 2 and at 8 hr after ingestion of each of two doses of each drug. Four pain ratings were recorded: mild, moderate, severe, and unbearable. Serum levels of each drug were measured before ingestion and midway in each test. Comparison of the responses in both tests indicated enhanced pain tolerance in the 8-hr as compared to the 2-hr test after drug ingestion. The carryover effects occurred despite a reduction in serum levels of drug between the two tests. A second study suggested that carryover effects were greater after aspirin than after placebo. The studies indicate that a drug-test interaction can occurr in the submaximum-effort tourniquet technique and may obscure expected treatment differences. The findings also suggest that investigators should consider the possibility of such interactions in the design of experiments employing this method.