Randomized, controlled trial of dextromethorphan/quinidine for pseudobulbar affect in multiple sclerosis

Abstract Objective To evaluate the efficacy and safety of DM/Q (capsules containing dextromethorphan [DM] and quinidine [Q]) compared with placebo, taken twice daily, for the treatment of pseudobulbar affect over a 12‐week period in multiple sclerosis patients. Methods A total of 150 patients were randomized in a double‐blind, placebo‐controlled study to assess pseudobulbar affect with the validated Center for Neurologic Study‐Lability Scale. Each patient also recorded the number of episodes experienced between visits, estimated quality of life and quality of relationships on visual analog scales, and completed a pain rating scale. Results Patients receiving DM/Q had greater reductions in Center for Neurologic Study‐Lability Scale scores than those receiving placebo ( p < 0.0001) at all clinic visits (days 15, 29, 57, and 85). All secondary end points also favored DM/Q, including the number of crying or laughing episodes ( p ≤ 0.0077), quality of life ( p < 0.0001), quality of relationships ( p = 0.0001), and pain intensity score ( p = 0.0271). DM/Q was well tolerated; only dizziness occurred with greater frequency than with placebo. Interpretation Results in multiple sclerosis patients were similar to those of a previous study in amyotrophic lateral sclerosis, demonstrating that DM/Q may be beneficial in treating potentially disabling pseudobulbar affect in a variety of neurological disorders. Ann Neurol 2006;59:780–787