Treatment of cataplexy

1. A method of treating cataplexy in a subject in need thereof, comprising administering to the subject a therapeutically effective amount of a compound of Formula (I):

or a pharmaceutically acceptable salt or ester thereof;

wherein R is a member selected from the group consisting of hydrogen, lower alkyl of 1 to 8 carbon atoms, halogen selected from F, Cl, Br and I, alkoxy containing 1 to 3 carbon atoms, nitro, hydroxy, trifluoromethyl, and thioalkoxy containing 1 to 3 carbon atoms;

x is an integer of 0 to 3, with the proviso that R may be the same or different when x is 2 or 3;

R 1 and R 2 are independently selected from the group consisting of hydrogen, lower alkyl of 1 to 8 carbon atoms, aryl, arylalkyl, cycloalkyl of 3 to 7 carbon atoms; or

R 1 and R 2 can be joined to form a 5 to 7-membered heterocycle substituted with a member selected from the group consisting of hydrogen, alkyl, and aryl groups, wherein the heterocycle can comprise 1 to 2 nitrogen atoms and 0 to 1 oxygen atom, wherein the nitrogen atoms are not directly connected with each other or with the oxygen atom;

wherein the subject has 3 or more cataplectic events per week when untreated.

2. The method of claim 1 , wherein x=0.

3. The method of claim 1 , wherein R 1 and R 2 are hydrogen and x=0.

4. The method of claim 1 , wherein the compound of Formula I is an enantiomer of Formula I substantially free of other enantiomers or an enantiomeric mixture wherein one enantiomer of Formula I predominates.

5. The method of claim 4 , wherein the enantiomer of Formula I predominates to the extent of about 98% or greater.

6. The method of claim 4 , wherein the enantiomer of Formula I is an enantiomer of Formula Ia:

or a pharmaceutically acceptable salt or ester thereof.

7. The method of claim 6 , wherein the enantiomer of Formula Ia is the (R) or (D) enantiomer.

8. The method of claim 6 , wherein the enantiomer of Formula Ia is the(S) or (L) enantiomer.

9. The method of claim 6 , wherein the enantiomer of Formula Ia predominates to the extent of about 98% or greater.

10. The method of claim 4 , wherein the enantiomer of Formula I substantially free of other enantiomers is the compound of Formula Ib or an enantiomeric mixture wherein the compound of Formula Ib predominates:

or a pharmaceutically acceptable salt or ester thereof.

11. The method of claim 10 , wherein the compound of Formula Ib predominates to the extent of about 90% or greater.

12. The method of claim 10 , wherein the compound of Formula Ib predominates to the extent of about 98% or greater.

13. The method of claim 1 , wherein the cataplexy is associated with narcolepsy.

14. The method of claim 1 , wherein the cataplexy is secondary to a condition that lowers hypocretin levels in the subject.

15. The method of claim 14 , wherein the condition is selected from the group consisting of brain tumor, astrocytomas, glioblastoma, glioma, subependynoma, craniopharyngioma, arterio-venous malformations, ischemic events, multiple sclerosis, head injury, brain surgery, paraneoplastic syndromes, Neimann-Pick type C disease, and encephalitis.

16. The method of claim 1 , wherein the therapeutically effective amount of the compound of Formula I is from about 0.01 mg/kg/dose to about 150 mg/kg/dose.

17. The method of claim 1 , wherein the therapeutically effective amount of the compound of Formula I is from about 1 mg/day to about 7000 mg/day.

18. The method of claim 1 , wherein the compound of Formula I is administered orally.

19. The method of claim 1 , wherein the compound of Formula I is administered in the form of a capsule or tablet.

20. The method of claim 1 , wherein the compound of Formula I is administered in the form of a capsule at a dose of about 150 mg to about 300 mg without any excipients.