Methods and compositions for the treatment of CNS-related conditions

1. A method of reducing the potential for an adverse effect in a human subject being treated for a CNS-related condition comprising orally administering once a day to a human subject in need thereof a pharmaceutical composition comprising:

5 to 40 mg memantine or a pharmaceutically acceptable salt thereof in an extended release dosage form, wherein said extended release memantine or pharmaceutically acceptable salt thereof provides a change in plasma concentration as a function of time (dC/dT) in the defined time period of 0 to 6 hours after administration, as measured in a single-dose human PK study, that is less than about 50% of the dC/dT provided by the same quantity of an immediate release form of memantine in said defined time period;

wherein the adverse effect is related to memantine; and

wherein the CNS-related condition is selected from the group consisting of Alzheimer's disease and dementia.

2. The method of claim 1 , wherein the dosage form comprises 12.5-40 mg of memantine or salt thereof.

3. The method of claim 1 , wherein the dosage form comprises 25-40 mg of memantine or salt thereof.

4. The method of claim 1 , wherein the extended release dosage form further comprises, ethyl cellulose, polyethylene glycol, hydroxypropylmethyl cellulose and polyvinylpyrrolidone.

5. The method of claim 1 , wherein said extended release memantine or a pharmaceutically acceptable salt thereof has an in vitro dissolution profile of less than 60% in four hours and less than 80% in six hours as measured using a USP type 2 (paddle) dissolution system at 50 rpm, at a temperature of 37±0.5° C. with water as a dissolution medium.

6. The method of claim 1 , wherein the extended release dosage form is co-administered with an AChEI, selected from the group consisting of donepezil, galantamine, rivastigmine and tacrine.

7. A method of treating a CNS-related condition comprising orally administering once a day to a human subject in need thereof:

(a) 5 to 40 mg memantine or a pharmaceutically acceptable salt thereof provided in an extended release dosage form, wherein said extended release memantine or pharmaceutically acceptable salt thereof provides a change in plasma concentration as a function of time (dC/dT) in the defined time period of 0 to 6 hours after administration as measured in a single-dose human PK study that is less than about 50% of the dC/dT provided by the same quantity of an immediate release form of memantine in said defined time period; and

(b) a therapeutically effective amount of an AChEI, or a pharmaceutically acceptable salt thereof,

wherein the CNS-related condition is selected from the group consisting of Alzheimer's disease and dementia.

8. The method of claim 7 , wherein said memantine or a pharmaceutically acceptable salt thereof and said AChEI or a pharmaceutically acceptable salt thereof are administered simultaneously.

9. The method of claim 7 , wherein said memantine or a pharmaceutically acceptable salt thereof and said AChEI or a pharmaceutically acceptable salt thereof are administered as a single composition.

10. The method of claim 7 , wherein said AChEI is selected from the group consisting of donepezil, rivastigmine, galantamine and tacrine.

11. The method of claim 7 , wherein said AChEI is donepezil.

12. The method of claim 7 , wherein the dosage form comprises 12.5-40 mg of memantine or salt thereof.

13. The method of claim 7 , wherein the dosage form comprises 25-40 mg of memantine or salt thereof.

14. The method of claim 7 , wherein the extended release dosage form further comprises, ethyl cellulose, polyethylene glycol, hydroxypropylmethyl cellulose and polyvinylpyrrolidone.

15. The method of claim 7 , wherein said extended release memantine or a pharmaceutically acceptable salt thereof has an in vitro dissolution profile of less than 60% in four hours and less than 80% in six hours as measured using a USP type 2 (paddle) dissolution system at 50 rpm, at a temperature of 37±0.5° C. with water as a dissolution medium.