Compounds and combinations thereof for treating neurological and psychiatric conditions

Abstract

Disclosed herein are methods of treating neurological or psychiatric diseases or disorders using a combination of an antidepressant, such as bupropion, and dextromethorphan. Related compositions and dosage forms are also described.

What is claimed is: 
     
         1 . A method of treating depression comprising: orally administering a dosage form to a human being in need thereof for at least 8 consecutive days; wherein the dosage form comprises a dextromethorphan and a paroxetine; wherein the human being receives a total daily dose of about 20 mg to about 180 mg of the dextromethorphan; wherein the dextromethorphan and the paroxetine are the only therapeutically active agents in the dosage form; wherein the human being is an extensive metabolizer of dextromethorphan; and wherein administering the dosage form corrects extensive metabolism of dextromethorphan. 
     
     
         2 . The method of  claim 1 , wherein the dextromethorphan is in the free base form or a salt form. 
     
     
         3 . The method of  claim 1 , wherein the paroxetine is in the free base form or a salt form. 
     
     
         4 . The method of  claim 1 , wherein a total daily dose of about 10 mg to about 70 mg of the paroxetine is orally administered to the human being. 
     
     
         5 . The method of  claim 1 , wherein the depression is major depressive disorder. 
     
     
         6 . The method of  claim 1 , wherein the depression is treatment resistant depression. 
     
     
         7 . The method of  claim 1 , wherein the dosage form is orally administered for at least 14 consecutive days. 
     
     
         8 . The method of  claim 1 , wherein the dosage form provides immediate release of the dextromethorphan. 
     
     
         9 . The method of  claim 1 , wherein the dosage form provides sustained release of the paroxetine. 
     
     
         10 . The method of  claim 1 , wherein the dosage form contains about 20 mg to about 90 mg of the dextromethorphan, and wherein the dosage form is orally administered to the human being once a day or twice a day. 
     
     
         11 . The method of  claim 1 , wherein the dosage form contains about 30 mg to about 60 mg of the dextromethorphan, and wherein the dosage form is orally administered to the human being once a day or twice a day. 
     
     
         12 . The method of  claim 1 , wherein the dosage form contains about 40 mg to about 50 mg of the dextromethorphan, and wherein the dosage form is orally administered to the human being once a day or twice a day. 
     
     
         13 . The method of  claim 1 , wherein the dosage form contains about 50 mg to about 70 mg of the dextromethorphan, and wherein the dosage form is orally administered to the human being once a day. 
     
     
         14 . The method of  claim 1 , wherein the dosage form contains about 60 mg to about 120 mg of the dextromethorphan, and wherein the dosage form is orally administered to the human being once a day. 
     
     
         15 . The method of  claim 1 , wherein the dosage form contains about 45 mg of a dextromethorphan salt, and wherein the dosage form is orally administered to the human being once a day or twice a day. 
     
     
         16 . The method of  claim 1 , wherein the dextromethorphan comprises a deuterium-modified dextromethorphan. 
     
     
         17 . The method of  claim 1 , wherein the dosage form is a capsule, a tablet, or a solution. 
     
     
         18 . The method of  claim 1 , wherein a dextromethorphan plasma level is increased as compared to orally administering the same amount of dextromethorphan alone. 
     
     
         19 . The method of  claim 1 , wherein the human being is converted to a poor metabolizer of dextromethorphan upon orally administering the dosage form. 
     
     
         20 . The method of  claim 1 , wherein the dosage form further comprises a pharmaceutically acceptable excipient. 
     
     
         21 . The method of  claim 1 , wherein the elimination half-life of dextromethorphan increases upon orally administering the dosage form.