Adults with painful osteoarthritis of the knee may find relief by rubbing on a gel containing the nonsteroidal anti-inflammatory drug (NSAID) diclofenac (sold as Arthrotec or Voltaren), results of a German study demonstrate.

Because oral NSAIDs often upset the stomach, Dr. Fritz U. Niethard and colleagues

from Universitatsklinikum Aachen studied the pain-relieving properties of diclofenac gel versus an inactive gel in more than 230 patients with osteoarthritis of the knee and “moderate” pain.

After a washout phase in which they discontinued analgesic medication, patients were instructed to rub the assigned gel into the affected knee four times daily for three weeks. Patients were permitted up to four tablets per day of acetaminophen 500 mg if needed.

The active NSAID gel began to work over the course of the first week, according to the researchers, with “peak” efficacy was reached during the second week and maintained over the third week.

According to diaries that the patients kept, diclofenac gel was significantly more effective than placebo gel in relieving their pain. Those on active treatment were more likely than those on placebo treatment to rate the effectiveness of the gel as good, very good, or excellent.

Side effects were virtually the same in the two groups, as was the need for rescue medication.

“Diclofenac gel ... should be considered as an appropriate first-line option for the treatment of pain in OA of small and large joints,” Niethard and his associates maintain.

This study was supported by Novartis Consumer Health.

SOURCE: Journal of Rheumatology December 2005.