Doxepin
"Had a brain injury, sleep 2 to 3 hours a night. Take Doxepin 10 mg I have found to take the capsule a part dump out about 5 mg of medicine.  I can sleep 6 to 7 hours and wake up feeling great. No hangover.  Even if I wake up during the night I can go back to sleep. This drug is wonderful if used correctly"