title: Unpredictable absorption of oral opioid medications in a quadriplegic patient with chronic enterocutaneous fistulas.
abstract: Although there is an abundance of literature on the acute management of enterocutaneous fistulas, there is a paucity of data on the chronic management of enterocutaneous fistulas. Their impact on oral pharmacotherapy, including their effect on the bioavailability of oral medications, is poorly understood. This case describes a 23-year-old quadriplegic male with a complex history of multiple abdominal surgeries presented with three persistent enterocutaneous fistulas. Diazepam and furosemide were among the patient's oral medications and had sufficient bioavailability to show efficacy on anxiety and pedal edema, respectively. Conversely, oral oxycodone and methadone were ineffective in controlling chronic pain despite high doses and aggressive titration. Due to inadequate pain control, the patient supplemented opioid medications with high doses of lorazepam and diazepam to augment psychological comfort. A trial of subcutaneous morphine successfully produced immediate analgesia, causing a marked reduction in benzodiazepine use. Enterocutaneous fistulas may reduce the bioavailability of oral medications to various degrees depending upon the medication. Further research is needed to elucidate the effect chronic enterocutaneous fistulas have on the bioavailability of oral medications. It is therefore important for clinicians to question the bioavailability of medications in the setting of enterocutaneous fistulas and poor clinical response.
authors.affiliation: University of Arizona College of Pharmacy and University of Arizona Medical Center, Tucson, Arizon, USA. viswesh@pharmacy.arizona.edu
authors.forename: Velliyur V
authors.initials: VV
authors.lastname: Viswesh
mesh_terms: D000284:Administration, Oral; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000627:therapeutic use; D001569:Benzodiazepines / Q000008:administration & dosage / Q000627:therapeutic use; D001682:Biological Availability; D002908:Chronic Disease; D059350:Chronic Pain / Q000188:drug therapy*; D006801:Humans; D007412:Intestinal Fistula / Q000150:complications*; D008297:Male; D008691:Methadone / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use; D009020:Morphine / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use; D010098:Oxycodone / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use; D011782:Quadriplegia / Q000150:complications*; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D001569:Benzodiazepines; D009020:Morphine; D010098:Oxycodone; D008691:Methadone