title: Rapid switching between transdermal fentanyl and methadone in cancer patients.
abstract: OBJECTIVE
  The aim of this study was to examine the clinical effects of switching from transdermal (TTS) fentanyl to methadone, or vice versa, in patients with a poor response to the previous opioid.
  
  
  METHODS
  A prospective study was carried out on 31 patients who switched from TTS fentanyl to oral methadone, or vice versa, because of poor opioid response. A fixed conversion ratio of fentanyl to methadone of 1:20 was started and assisted by rescue doses of opioids, and then doses were changed according to clinical response. Pain and symptom intensity, expressed as distress score, were recorded before switching doses of the two opioids and after subsequent doses. The number of changes of the daily doses, time to achieve stabilization, and hospital stay were also recorded.
  
  
  RESULTS
  Eighteen patients were switched from TTS fentanyl to methadone, and seven patients were switched from methadone to TTS fentanyl. A significant decrease in pain and symptom intensity, expressed as symptom distress score, was found within 24 hours after switching took place in both directions. Unsuccessful switching occurred in six patients, who were subsequently treated with an alternative therapy.
  
  
  CONCLUSIONS
  A rapid switching using an initial fixed ratio of fentanyl to methadone of 1:20 is an effective method to improve the balance between analgesia and adverse effects in cancer patients with poor response to the previous opioid. No relationship between the final opioid dose and the dose of the previous opioid has been found.
authors.affiliation: Anesthesia and Intensive Care Unit, La Maddalena Cancer Center, Via San Lorenzo 312, 90146 Palermo, Italy. terapiadeldolore@la-maddalena.it
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Mercadante
authors.forename: Patrizia
authors.initials: P
authors.lastname: Ferrera
authors.forename: Patrizia
authors.initials: P
authors.lastname: Villari
authors.forename: Alessandra
authors.initials: A
authors.lastname: Casuccio
mesh_terms: D000279:Administration, Cutaneous; D000701:Analgesics, Opioid / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008691:Methadone / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications; D010146:Pain / Q000188:drug therapy* / Q000209:etiology; D010147:Pain Measurement; D011446:Prospective Studies; D016896:Treatment Outcome
chemical_list: D000701:Analgesics, Opioid; D008691:Methadone; D005283:Fentanyl