MorphiDex (R) (MS : DM) double-blind, multiple-dose studies in chronic pain patients

Preclinical and double-blind single-dose placebo-controlled studies demonst rated that MorphiDex(R) (MS:DM), a 1:1 ratio of morphine sulfate (MS) to de xtromethorphan hydrobromide (DM), provides significantly greater analgesia than an equal dose of immediate release MS, with a faster onset, and a dura tion of greater than or equal to 8 h. The analgesic effect of MS:DM compare d to MS was evaluated in 2 double-blind, multiple-dose studies in 321 patie nts with cancer and other chronic pain: a crossover study that consisted of two 2-wk periods and a 4-wk parallel study. As specified in the study prot ocols, patients took sufficient MS or MS:DM to achieve satisfactory pain co ntrol. In the crossover study, the MS:DM group required half as much morphi ne as the MS group to achieve satisfactory pain control (80 mg and 162 mg r espectively). The interval between doses and the time from the last dose of the day to the first dose of the next day were significantly longer for MS :DM compared to MS. In the parallel study, MS:DM also provided pain control at a significantly lower dose. After four weeks of treatment, the mean dai ly dose of MS increased while there was little change in the MS:DM mean dai ly dose (P = 0.025) to maintain satisfactory pain control. More patients pr eferred MS:DM to run-in MS than preferred MS to run-in MS 1(P = 0.026). The addition of DM to MS did not increase the incidence of adverse eve nts, wh ich were those commonly associated With opioid use. These studies confirm t hat MS:DM provides satisfactory pain relief but at a significantly lower mo rphine daily dose. J Pain Symptom Manage 2000;19:S37-S41. (C) U.S. Cancer P ain Relief Committee, 2000.