Analgesic efficacy of controlled-release dihydrocodeine. A comparison of 60, 90 and 120 mg tablets in cold-induced pain.

A prospective, double-blind, single-dose placebo-controlled four-part crossover study of 12 healthy volunteers was carried out to compare the analgesic efficacy of controlled-release dihydrocodeine tablets 60, 90 and 120 mg (DHC Continus tablets, Napp Laboratories) in cold-induced pain. Subjects received each of the four treatments in a random order using a latin square design. On each of the four study days, the volunteers performed cold pressor tests, before dose and again at 4, 8 and 12 hours after dose. Subjects rated their pain continuously over a 120-second period using a visual analogue scale. At 4 hours there was a significant reduction in pain in subjects who received 120 mg or 90 mg tablets compared with placebo, and in subjects who received 120 mg tablets compared with those who received 60 mg tablets. At 8 hours, 120 mg and 90 mg dihydrocodeine were still better than placebo. There was no significant difference in side effects between treatments.