The Collaborative International Dictionary of English v.0.48:
drained \drained\ 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]