Is medical debt negotiable?

I racked up a $5,000 bill for a night in the ER and soon after I didn't pay it was handed over to a debt collector. I've tried to negotiate with them and make a smaller settlement but nothing is working. They are demanding the full amount, and threatening to file a lawsuit against me so they can garnish my wages. Should I bite the bullet and just try to pay the full amount(even though I don't have the money), or is there any other way of going about this to pay a smaller amount?