Ultra low dose doxepin and methods of using the same to treat sleep disorders

1. A method for treating insomnia comprising orally administering to a patient doxepin or a pharmaceutically acceptable salt thereof in a daily dosage ranging from about 0.0001 to about 0.2 milligrams without administering other insomnia or sleep medications.

2. The method of claim 1 , wherein the pharmaceutically acceptable salt of doxepin is the hydrochloride salt thereof.

3. The method of claim 1 , wherein the daily dosage ranges from about 0.001 to about 0.1 milligrams.

4. The method of claim 1 , wherein the daily dosage is about 0.01 to about 0.099 milligrams.

5. The method of claim 1 , wherein the insomnia is a non-chronic insomnia.

6. The method of claim 5 , wherein the non-chronic insomnia is a transient or a short term insomnia.

7. The method of claim 1 , wherein the insomnia is selected from the group consisting of onset insomnia and maintenance insomnia.

8. The method of claim 1 , wherein the patient is not suffering from depression.

9. The method of claim 1 , wherein the patient is suffering from depression.

10. A method of shortening the time required to achieve a maximum plasma concentration of doxepin in a patient receiving doxepin therapy comprising orally administering to the patient about 0.0001 milligrams to about 0.2 milligrams of doxepin in a pharmaceutical composition, wherein the doxepin is administered without food and without the administration of other insomnia or sleep medications.

11. A method of shortening the time required to achieve sleep onset comprising orally administering to the patient about 0.0001 milligrams to about 0.2 milligrams of doxepin in a pharmaceutical composition, wherein the doxepin is administered without food and without the administration of other insomnia or sleep medications.