Pharmaceutical compositions comprising dextromethorphan and quinidine for the treatment of neurological disorders

Abstract

Pharmaceutical compositions and methods for treating neurological disorders by administering same are provided. The compositions comprise dextromethorphan in combination with quinidine.

1 . A method for treating neuropathic pain, the method comprising administering to a patient in need thereof dextromethorphan in combination with quinidine, wherein an amount of dextromethorphan administered comprises from about 20 mg/day to about 200 mg/day, and wherein an amount of quinidine administered comprises from about 10 mg/day to less than about 50 mg/day. 
     
     
         2 . The method of  claim 1 , wherein the dextromethorphan and the quinidine are administered as one combined dose per day. 
     
     
         3 . The method of  claim 1 , wherein the dextromethorphan and the quinidine are administered as at least two combined doses per day. 
     
     
         4 . The method of  claim 1 , wherein the amount of quinidine administered comprises from about 20 mg/day to about 45 mg/day. 
     
     
         5 . The method of  claim 1 , wherein the amount of dextromethorphan administered comprises from about 20 mg/day to about 60 mg/day. 
     
     
         6 . The method of  claim 1 , wherein at least one of the quinidine and the dextromethorphan is in a form of a pharmaceutically acceptable salt. 
     
     
         7 . The method of  claim 1 , wherein at least one of the quinidine and the dextromethorphan is in a form of a pharmaceutically acceptable salt selected from the group consisting of salts of free acids, inorganic salts, salts of sulfate, salts of hydrochloride, and salts of hydrobromide. 
     
     
         8 . The method of  claim 1 , wherein the quinidine comprises quinidine sulfate and the dextromethorphan comprises dextromethorphan hydrobromide, and wherein an amount of quinidine sulfate administered comprises from about 10 mg/day to 30 mg/day and wherein an amount of dextromethorphan hydrobromide administered comprises from about 30 mg/day to about 90 mg/day. 
     
     
         9 . The method of  claim 8 , wherein about 20 mg/day quinidine sulfate is administered per day. 
     
     
         10 . The method of  claim 9 , wherein about 60 mg/day dextromethorphan hydrobromide is administered per day. 
     
     
         11 . The method of  claim 8 , wherein about 30 mg/day quinidine sulfate is administered per day. 
     
     
         12 . The method of  claim 11 , wherein about 60 mg/day dextromethorphan hydrobromide is administered per day. 
     
     
         13 . The method of  claim 1 , wherein the dextromethorphan and the quinidine are administered in a combined dose, and wherein a weight ratio of dextromethorphan to quinidine in the combined dose is about 1:1.25 or less. 
     
     
         14 . The method of  claim 13 , wherein the weight ratio of dextromethorphan to quinidine is about 1:0.75 or less. 
     
     
         15 . The method of  claim 1 , wherein the amount of quinidine administered is from about 10 mg/day to about 45 mg/day. 
     
     
         16 . The method of  claim 1 , wherein the amount of quinidine administered is from about 10 mg/day to about 30 mg/day. 
     
     
         17 . The method of  claim 1 , wherein the amount of quinidine administered is from about 10 mg/day to about 20 mg/day.