On the sensitivity of the tourniquet pain test.

Twenty-four chronic pain patients were given, on each of 4 successive days, oral doses of 60 mg morphine, 60 mg codeine, 600 mg aspirin and placebo, using a double-blind counterbalanced design. Two hours after ingestion, subjective pain estimates and tourniquet pain scores were obtained. Variability of the tourniquet pain scores was too great for differences in response to the analgesics to be significant. However, differences in pain estimates were also too small to discriminate among the drugs, and the lack of sensitivity may be a function of pain chronicity. The tourniquet techniques will continue to be useful until there is a purely objective measure of the severity of clinical pain.