Clomipramine and mianserin in chronic idiopathic pain syndrome. A placebo controlled study.

The reduction of pain by two antidepressants, clomipramine and mianserin, was, in this study on 253 patients with chronic idiopathic pain syndrome, found to be not better than a placebo when all patients were compared independently of the classification of pain. The improvement rate was around 40% after 6 weeks of treatment when using a 50% or better reduction in pain level. However, in patients who fulfilled a checklist definition of minor to major depression (30% of the total patient material) clomipramine was superior to mianserin and placebo with an improvement rate of 75% after 6 weeks. Using pain curves over time as outcome measure in the various clinical pain categories it was found that both mianserin and clomipramine seemed superior to placebo in patients with tension headache, but in patients with low back pain syndrome placebo was superior to the two antidepressants. No difference among the three treatments was found in patients with burning mouth syndrome or in patients with abdominal pain. These differences underline the importance of studying specific pain syndromes rather than composite groups of patients with idiopathic pain. The clinical significance of these pain curves needs further placebo controlled investigations.