Depending on how sensitive the test was for, then one possible cause of false cocaine positive is lidocaine. Your other medication will show positives for opiates and benzodiazepine.
You need to show your prescriptions to the testing people. We always advise people to declare all their medication when going for blood tests.
Your lidoderm patch contains lidocaine, this is structurally similar to cocaine so may show up as a false cocaine positive.