Long-term safety of MorphiDex.

Abstract

More than 2200 subjects were enrolled in the MorphiDex (MS:DM) development program, with a 1:1 (weight:weight) ratio of morphine sulfate (MS) to dextromethorphan hydrobromide (DM). Of the 1400 subjects exposed to MorphiDex, more than 350 subjects were treated for at least 6 months, and over 200 subjects were treated for a year or longer. The clinical population comprised an approximately equal number of men (46.2%) and women (53.8%), ranging in age from 16 to 96 years, and mostly Caucasian (91.8%). The most frequent (54.8%) daily dose of MorphiDex for subjects enrolled in the clinical program was 120 mg or less. Slow DM metabolizers took significantly lower daily doses of MorphiDex than rapid metabolizers without a significant difference in the incidence of adverse events. Plasma bromide concentrations were low and showed a wide margin of safety for both slow and rapid DM metabolizers. There were no clinically significant treatment-related changes in clinical laboratory tests, neurological examinations, or vital signs. The most common adverse events seen in the multiple dose controlled studies were nausea, dizziness, vomiting, somnolence, constipation, confusion, asthenia, headache, and pruritus. With long-term treatment, the prevalence of adverse events was greatest during the first month of MorphiDex exposure and then decreased over time. The incidence of constipation remained fairly constant over time.