Fiorinal with codeine in the treatment of tension headache--the contribution of components to the combination drug.

The contribution of the Fiorinal and codeine phosphate components to the effectiveness of the Fiorinal with Codeine combination in the treatment of tension headache symptoms was evaluated in a randomized, placebo-controlled, multicenter double-blind study. Patients admitted to the trial took two capsules of Fiorinal with Codeine, Fiorinal alone, codeine alone, or placebo during each of two tension headache attacks. Immediately before and at intervals up to four hours after drug ingestion, patients rated pain severity, pain relief, the tense and uptight feeling, and muscle stiffness. The response to treatment was evaluated in 154 patients. Despite a high placebo response, a factor known to obscure the contribution of components, Fiorinal and codeine were each found to contribute significantly to the therapeutic effect of the Fiorinal with Codeine combination. Statistical or borderline superiority of the combination drug over Fiorinal alone was seen most frequently at the early evaluations, a finding that reflected the rapid onset of action of codeine. Statistically significant differences between Fiorinal with Codeine and codeine alone seen principally at the later assessments reflected the long duration of action of the Fiorinal component. The frequency of adverse reactions did not differ significantly among the four study groups.