Mild analgesics evaluated with the “Submaximum Effort Tourniquet Technique”

Abstract

According to Beecher (1957, 1968) the effects of analgesics on experimental pain are difficult to evaluate, because experimental pain is usually less intense and less threatening than pathological pain, lasts for shorter time, induces less uncertainty and can be discontinued deliberately. The “Submaximum Effort Tourniquet Test” developed by his group has been advocated as a method sensitive to even mild analgesics.

When the effects of Placebo, C- 44′328-Ba¹ and Dextropropoxyphene were assessed by means of this method in 30 healthy male volunteers in a double- blind, cross- over trial, the over- all analysis of variance failed to show significant group-differences.

When psychological factors, — i.e. level of anxiety, use of coping behavior in order to get distracted from pain, and style of relating to the experimenter (assessed by rating of interviews) were taken into account, the calm group (n=14) with low levels of anxiety, low use of coping behavior and relaxed manner of relating, showed a trend toward better discrimination between placebo and analgesics than the aroused group (n=11).

In the two extreme groups (most calm, n=7) and most aroused (n=6) the response to the individual four trials was significantly different (P<0.05). In the former group discrimination occurred between the analgesics on one hand and placebo and “no treatment” on the other, while in the latter discrimination occurred only between C- 44′328-Ba and all other conditions.

The assumption of Beecher, that high levels of anxiety are necessary for the experimental testing of analgesics seems, according to our findings, to be correct for the group of narcotics, while for mild analgesics the best experimental situation might be one, which permits the subject to remain calm and relaxed.