Well as the original states "...and he fell to the ground, unconscious." how about unconsciousness for the initial damage (like drow poison) followed by 2d6 or 2d8 Con damage as the secondary damage. After all 1 minute is less than 1 hour.
Although if it was up to me it would be 1d4 Con every 15 minutes but the rules don't work that way.
Regards
Mortis
I'm never adverse to including a bit of damage. Well as long as it isn't to my character.I like the unconsciousness, although I'd fold in some damage too. Maybe a lot less damage for the initial effects?
Maybe unconscious for 1 hour plus 1d4 Con primary, unconscious for 1d3 hours plus 1d12 Con secondary?
I'm never adverse to including a bit of damage. Well as long as it isn't to my character.
I prefer 2d6 to 1d12 for the secondary damage (along with the unconscious bit of course). Not much difference I know.
Regards
Mortis
Ready for skills and feats? Stick the extra ranks into Move Silently, maybe? Stealthy for the feat, perhaps?