[Comparative double-blind study of the analgesic activity of fosfosal (UR-1521) in patients with musculoskeletal and articular pain (author's transl)].

Fosfosal or 2-phosphonoxybenzoic acid is a new analgesic drug, whose analgesic activity and side effects have been determined in a double blind clinical study in comparison with placebo. The study has been done with 60 outpatients, of both sexes, which suffered musculoskeletal and arthritic pains. Patients were treated with fosfosal or placebo for eight days. The daily dose of fosfosal was 1 gram three times a day, once every 6-8 hours. The results obtained show that fosfosal has a clear analgesic activity, statistically significant versus placebo in all the parameters that were measured: pain severity, activity impairment and insomnia. The overall evaluation of the group of patients treated with fosfosal showed a marked improvement with a difference statistically significant with respect to the control group treated with placebo (p less than 0.001). The distribution of results in the fosfosal treated group was as follows: poor, 1; regular, 8; good, 10 and excellent, 6. The distribution in the placebo group was as follows: poor, 15; regular, 3; good, 2 and excellent, 0. The marked analgesic activity, the absence of side effects and the excellent gastric tolerance suggest that fosfosal is a promising new analgesic drug useful for the treatment of painful syndromes of several etiologies.