Conditions: Central Neuropathic Pain Multiple Sclerosis
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 209
Healthy volunteers: no

Brief summary:
The objectives of the study are to evaluate the safety, tolerability, and efficacy of 3 doses of AVP-923 capsules in the treatment of central neuropathic pain in participants with multiple sclerosis.

Detailed description:
The objectives of the study are to evaluate the safety, tolerability, and efficacy of 3 doses of AVP-923 (dextromethorphan \[DM\]/quinidine \[Q\]) capsules containing either 45 mg DM and 10 mg Q (AVP-923-45) or 30 mg DM and 10 mg Q (AVP-923-30) or 20 mg DM and 10 mg Q (AVP-923-20) compared to placebo, for the treatment of central neuropathic pain in a population of participants with multiple sclerosis (MS) over a 12-week period. The MS participant population enrolled includes participants with relapsing-remitting multiple sclerosis (RRMS) and participants with secondary progressive multiple sclerosis (SPMS).

Arms:
arm 1: None arm 2: None arm 3: None arm 4: None

Interventions: intervention 1: AVP-923-45 intervention 2: AVP-923-30 intervention 3: AVP-923-20 intervention 4: Placebo
Intervention descriptions: intervention 1: AVP-923-45 (dextromethorphan 45 mg/quinidine 10 mg) capsules administered once daily for first 7 days followed by twice daily for 11 weeks of the study to complete 12 weeks of treatment. intervention 2: AVP-923-30 (dextromethorphan 30 mg/quinidine 10 mg) capsules administered once daily for first 7 days followed by twice daily for 11 weeks of the study to complete 12 weeks of treatment. intervention 3: AVP-923-20 (dextromethorphan 20 mg/quinidine 10 mg) capsules administered once daily for first 7 days followed by twice daily for 11 weeks of the study to complete 12 weeks of treatment. intervention 4: Matching placebo capsules administered once daily for first 7 days followed by twice daily for 11 weeks of the study to complete 12 weeks of treatment.

Protocol document: