- Presence of any illness or medication use that is judged to interfere with the trial. For example: skin irritations around the knee such as psoriasis; bleeding disorders or anticoagulant use that would be contraindications for acupuncture; diabetes due to the increased possibility of sensitivity to heat pain; and use of opiate medications and other substances of abuse that may influence the patient's experience of analgesia. (Due to the potential risk that prescription or non-prescription medication use can confound our results, we may perform a urine toxicology screen to verify patient's medication status during Session 1.)