I would extend credit. You will get burned on a certain percent, think of it as the cost of doing business. You will also be able to get some to make regular payments of 5-10 dollars per month. Some will settle up the bill when they can, (no really, some will do that,.. well at least one or two might or would if they didn't need the money for that new digital TV) You will be your own little miniature HMO but without the monthly CAP check.
But overall I think it would be a positive. Emotionally, not financially. (I am thinking of Ampicillin and Atenolol not Januvia or Actos). It would not be possible to extend credit if you are thinking of brand name patent meds.
It would not be a great business decision, but I would extend the credit.