Parenteral dipyrone versus diclofenac and placebo in patients with acute lumbago or sciatic pain: randomized observer-blind multicenter study.

Two hundred and sixty patients with lumbago or sciatic pain participated in a multicenter observer-blind randomized trial to compare the efficacy and tolerability of dipyrone 2.5 g, diclofenac 75 mg, and placebo administered as an intramuscular injection once daily for the duration of one to two days. The effectiveness of the test treatments in relieving sciatic pain was measured by a visual analog scale (VAS) before and 30 minutes, 1, 2, 3, 6 and 24 hours after each injection. In addition, the patient's general well-being was measured on a 5-point rating scale on day 0, 1 and 2. At the end of the trial, the patients evaluated the overall efficacy of the study drugs on a 5-point rating scale. Minimal finger-toe distance was measured every day of the trial. Pain intensity on VAS (primary endpoint) showed a significantly greater reduction with dipyrone than with diclofenac or placebo between 1 and 6 hours after application (p < 0.01) and at the end of the trial (after 48 hours). Improvement in general well-being and minimal finger-toe distance was greatest in the dipyrone group. 59% of the patients with dipyrone assessed the overall efficacy as "excellent" or "very good", compared with 30% with diclofenac, and 18% with placebo. Adverse reactions were reported in only 7 patients (3%), 4 (5%) in the dipyrone, 1 (1%) in the diclofenac, and 2 (2%) in the placebo group.