Propoxyphene napsylate compared to methadone for opiate dependence.

When high single doses of propoxyphene napsylate (PN) were given to patients on a methadone maintenance program, results indicated that, to avoid undesirable side effects, the dose should not exceed 600 mg. However, when PN was given in divided doses (800 mg/day in two equal doses), no significant adverse reactions were noted. In the double-blind comparison of 800 mg PN in two divided doses versus 20 mg methadone, 10 mg methadone, or placebo methadone, it was found that PN (1) did not alleviate withdrawal symptoms in patients previously maintained on 20 mg methadone, (2) produced a slightly overmedicated effect in the detoxified group of ex-methadone patients, and (3) compared favorably to 10 mg methadone in suppressing withdrawal symptoms without producing evidence of overmedication in those patients previously stabilized on a methadone maintenance dose of 10 mg. It is concluded that on a mg for mg basis, PN at a dose of 80-times that of methadone will relieve withdrawal symptoms in the treatment of mildly addicted patients requiring 10 mg methadone or less per day.