There are not many, but there are a few. You would not be a candidate for any PRP procedure if:
You have an active, blood born cancer
If you have platelet dysfunction
If you have an active infection at the site of injection
If you are pregnant
If you are taking any blood thinner medications
There are a few simple requirements around medication and over the counter medications:
You have to wait 1 month for a PRP procedure after taking steroids
You have to wait weeks after regularly taking any NSAIDS
You have to be off Aspirin for 1 week before your procedure (unless it is baby aspirin)