Clinical evaluation of mild analgesics in post partum pain.

1 The design of a clinical study evaluating mild analgesics in post partum patients is dependent on the purpose of the study. Work intended to determine whether a compound has any analgesic properties, requires a different design from a study positioning a drug in the continuum of available oral analgesics. A vital aspect of a well designed study is randomization of the treatments. The level of initial pain and the type of pain must also be stratified. The use of a cross-over design can decrease patient variation and is therefore very valuable. However, order effects need to be measured. 2 The parameters obtained from the data extend beyond the directly elicited to statistically derived variables. We have derived a method to assign mathematically a numerical score to each patient's verbal report. 3 To reach a meaningful conclusion, one should base the evaluation of the compound on several studies. The interpretation of data from one study must be made with great caution, because of individual variation. In the magnitude of the response some experimenters have found differences between uterine cramp and episiotomy pain, but these have not been consistently reproduced by others.