adj. having lost much energy or emotion from vigorous activity; -- of people; as, the day's events left her completely drained of strength. [ WordNet 1.5 ]
2. having resources completely depleted. Syn. -- depleted. [ WordNet 1.5 ]
3. having no power remaining; -- of a battery. Syn. -- run-down. [ WordNet 1.5 ]
to go down the drain 1. to be consumed in profitless activity; to be wasted; to become worthless. 2. to vanish or cease existing. [ PJC ]