Monitoring Opioid Use for Managing Chronic Pain

A 53-year-old woman with chronic low back pain presented for a prescription refill of hydrocodone/acetaminophen. She had partial paralysis from a thoracic spinal cord infarction secondary to aortic dissection from prior cocaine use and reported taking hydrocodone on that day but no recent illicit drug use. Urine immunoassay drug screen results were negative overall but positive for cocaine. How would you proceed?