Aurilio, C., Pace, M.C., Pota, V., Sansone, P., Barbarisi, M., Grella, E., & Passavanti, M.B. (2009). Opioids switching with transdermal systems in chronic cancer pain. Journal of Experimental & Clinical Cancer Research, 28, 61.

To evaluate the analgesic and side effects that result from switching between transdermal buprenorphine and transdermal fentanyl

Patients had an initial screening visit so investigators could obtain historical data. Patients who met inclusion criteria returned one week later for recruitment. Each patient received a diary in which to rate pain each morning, on a visual analog scale (VAS), and in which to record use of rescue pain medication. Any patients who had taken buprenorphine 70 mcg/hour continuously during the prior week and who had suffered side effects and refractory pain had his or her patch replaced by a 25 mcg/hour transdermal fentanyl patch. The fentanyl patch was positioned at a site different from the site of the previous patch. Patients who had taken fentanyl 75 mcg/hour during the prior week and who had suffered similar side effects and pain were switched to a 52.5 mcg/hour transdermal buprenorphine patch positioned on a different skin site. Rescue medication, 20 mg immediate-release oral morphine up to three times daily, was prescribed to each patient. Patients were followed for four weeks and seen weekly in the clinic for study assessments.

• The sample consisted of 32 patients.
• Mean patient age was 62 years; age range was 42–79 years.
• The sample was 46.8% female and 53.2% male. 
• The sample included multiple cancer diagnoses. The most frequent diagnoses were prostate, lung, and stomach cancers.
• Patients had chronic pain that had been treated for the previous three months; inadequate analgesia; and the presence of adverse events, such as sedation, dysphoria, nausea, vomiting, or constipation.
• Patients were excluded from the study if they received chemotherapy or radiotherapy cycles within the study period.

This was a single-site, outpatient study conducted in Naples, Italy.

The was a prospective trial.

• A 100-mm visual analog scale (VAS) was used to measure pain.
• Mean weekly ratings were recorded according to the Present Pain Intensity (PPI) scale (0 = no pain, 5 = excruciating).
• A 15-item Pain Rating Index (PRI), adapted from the Short-Form McGill Pain Questionnaire, was used.
• Dose of rescue pain medication taken (mg/day) was recorded.
• Adverse events were recorded as present or absent in response to questions about nausea-vomiting, constipation, and dysphoria.
• Level of sedation was rated on a four-point scale with 0 = no sedation and 3 = severe sedation.

• Compared to baseline values, VAS scores decreased significantly (p < 0.0001) after each week of treatment.
• In both groups, authors noted a significant reduction in PPI scores at each visit (p < 0.0001). At weeks 3 and 4, data regarding all patients showed a significant reduction in PRI (p < 0.0001) and a reduction in use of rescue medication (p < 0.0001).
• The number of patients with constipation decreased. Nausea or vomiting persisted only in patients with gall bladder and gastric cancers (n = 3).
• In both groups, dysphoria and sedation disappeared completely after the first week.

Findings indicate that, by replacing burprenorphine and fentanyl transdermal delivery with a 50% reduction in the new opioid dose, investigators achieved a significant reduction in pain and the need for short-term rescue medication.

• The study had a small sample size, with fewer than 100 patients.
• The study had a risk of bias in the VAS reporting because there was no blinding.
• Study duration was only four weeks; long-term efficacy of the intervention in the management of chronic pain management is unknown.

This study did not use equianalgesic doses when opioids were switched. This suggests that, at least initially, lower doses of the new drug may have been effective and reduced side effects. Further studies are warranted to continue the development of safe and effective opioid-switching methods.