I'm pretty sure I know the answer to this, but...
If someone is already asleep from their first failed save against Drow poison, all Delay Poison is going to do is keep them from having to make the 2nd save for the duration, correct? It's not going to cancel the sleep and wake them up sooner than the 1 minute initial effect, correct?
{Wicked smile} I like the possibilities of this. If you cast delay poison, it seems as if it may "delay" the second save, keeping the target unable to attempt to wake up til the effects of delay poison are over.
Cruel wicked drows :-)