Pirprofen, naproxen and placebo in the treatment of primary dysmenorrhoea.

In a double-blind between-patient clinical trial, 82 patients were admitted to the study and after a preliminary period with placebo administered in single-blindness, they were divided into two groups: "placebo-responders" and "placebo non-responders". Responders were treated with pirprofen capsules (400 mg, b.i.d.) or placebo capsules b.i.d.; non-responders were treated with pirprofen capsules (400 mg, b.i.d.) or naproxen capsules (250 mg, b.i.d.) according to two different randomisation lists, for four menstrual cycles. A complete medical examination, including evaluation of associated symptomatology, menstrual flow entity and global efficacy, was performed after each cycle. In the responders group results were significantly better with pirprofen than with placebo after only the second cycle of treatment (p less than 0.01). In the non-responders group both treatments showed "good" or "excellent" results in more than 80% of patients in all cycles. In all patients there were no significant differences in the evaluation of the menstrual flow entity, of the associated symptomatology and of the number of side-effects.