Comparison of electromotive drug administration with ketorolac or with placebo in patients with pain from rheumatic disease: a double-masked study

Abstract

This study was undertaken to assess the efficacy of ketorolac compared with placebo when delivered by electromotive drug administration (EMDA) in patients with pain from rheumatic disease. In EMDA, or iontophoresis, a low-intensity electric current is applied over the skin to deliver medication into body tissues. Although EMDA has been used to treat patients with various diseases, controlled studies are lacking in patients with rheumatic disease. This double-masked study included 60 patients (43 women and 17 men) aged 31 to 80 years with the following conditions: 12, epicondylitis; 30, scapulohumeral periarthritis; 10, gonalgia; and 8, metatarsalgia. They were divided randomly by a physician into 2 groups of 30 patients each for 5 sessions of active treatment (30 mg of ketorolac) or placebo (5 mL of normal saline). Treatment took place every other day for 20 minutes. Immediately before and after the five treatment sessions and 7 days after treatment ended, both patient and physician measured the degree of pain using a categoric scale (no pain, slight pain, intermediate pain, strong pain, and very strong pain) and evaluated pain intensity using the Scott and Huskisson Visual Analogue Scale (VAS). Seven days after treatment ended, both physician and patient judged the result of treatment using a second categoric scale (no improvement or intermediate, good, or very good result). Both ketorolac and placebo provided immediate, significant pain relief when delivered by EMDA, but only those patients receiving ketorolac experienced a further reduction in pain 7 days after treatment; those receiving placebo experienced a slight increase in pain. VAS values differed significantly between the two groups. Poor results (no improvement) were significantly higher in the placebo-treated group, while good results were significantly higher in the ketorolac-treated group. No patient reported any adverse effects during treatment. This study demonstrates that ketorolac relieves pain when delivered by EMDA and offers longer-lasting pain relief than does placebo.