@dizzywolf,
There could be other humane solutions than just the absent vet.
Just out of curiosity...because renal failure does NOT occur overnight but over an extended period of time, why didn't they take care of this end-of-life matter for their beloved pet BEFORE this weekend?
I'm not a vet but you MIGHT create a living hell worse than the dog is suffering at the moment with an improper dosage. Members here are trying to advise the best way for the suffering dog they know how. However, people who use negative heavy-handed critical tactics are wrong to do so.
Seek out an emergency pet clinic 'cause more than liklely (unless you live in a rural area) there are emergency pet facilities in most areas that can euthanize the dog if you seek them out. Why not list what city they're located and I'll bet you we can find a facility within a 25 mile radius.