Do predictors exist for the therapeutic effect of 5-HT3 receptor antagonists in fibromyalgia?

From the findings outlined below, there are no reliable predictors of the therapeutic effect of the 5-HT3-receptor antagonists in fibromyalgia. Neither clinical change in pain and vegetative symptoms, nor alterations in biochemical parameters are appropriate predictors of response. The accompanying psychological changes in the form of depressive disorders appear to be somewhat predictive of decreased therapeutic effect, if such definitive statements can be applied to individual cases. If, following new trials, it becomes possible to judge the response of patients to therapy after 3-5 days treatment with 2 mg intravenous tropisetron then predictors will be unnecessary in practice.