AAN: Combo Drug Effective for Pseudobulbar Affect
Open-label study demonstrates long-term efficacy of dextromethorphan and low-dose quinidine
WEDNESDAY, April 14 (HealthDay News) -- Dextromethorphan and low-dose quinidine -- a combination known as DMQ -- shows long-term efficacy in helping control the involuntary episodes of laughing and crying associated with pseudobulbar affect (PBA), according to research presented at the annual meeting of the American Academy of Neurology, held from April 10 to 17 in Toronto.
Erik P. Pioro, M.D., of the Cleveland Clinic, and colleagues studied 283 patients with PBA and multiple sclerosis or amyotrophic lateral sclerosis who were randomly assigned to receive dextromethorphan 30 mg plus quinidine 10 mg, dextromethorphan 20 mg plus quinidine 10 mg, or placebo for 12 weeks. Of these, 253 (89.4 percent) chose to enroll in a subsequent open-label study and received dextromethorphan 30 mg plus quinidine 10 mg for an additional 12 weeks.
From the start to the end of the open-label study, the researchers found that the mean test score on the Center for Neurologic Study-Lability Scale, which measures frequency and severity of PBA, decreased by a significant 2.7 points. In the groups that had previously received dextromethorphan 30 mg plus quinidine 10 mg and dextromethorphan 20 mg plus quinidine 10 mg, they found that the mean score decreased by 2.6 and 2.4 points, respectively. In the group which had previously received placebo, they found that the mean score decreased by 3.1 points.
"Our findings represent the first long-term results showing DMQ is effective in helping to control this debilitating condition afflicting patients with neurologic diseases or injuries," Pioro said in a statement. "Currently, there are no FDA-approved treatments for PBA, which is problematic because currently used off-label treatments are often ineffective or may have unacceptable side effects."
The study was supported by Avanir Pharmaceuticals Inc., which holds a patent for the dextromethorphan-quinidine combination; several authors disclosed financial relationships with Avanir and other pharmaceutical companies.