The aim of this study was to compare the analgesic and adverse effects, doses, as well as cost of opioid drugs, supportive drug therapy and other analgesic drugs in patients treated with oral sustained-release morphine, transdermal fentanyl, and oral methadone.

One hundred and eight cancer patients, no longer responsive to opioids for moderate pain, were selected to randomly receive initial daily doses of 60mg of oral sustained-release morphine, 15mg of oral methadone, or 0.6mg (25μg/h) of transdermal fentanyl. Oral morphine was used as breakthrough pain medication during opioid titration. Opioid doses, pain intensity, adverse effects, symptomatic drugs, were recorded at week intervals for 4weeks. Costs of opioid therapy, supportive drugs, and other analgesic drugs were also evaluated.

Seventy patients completed the 4weeks period of study. Five, five, and four patients, treated with oral morphine, transdermal fentanyl, and oral methadone, respectively, required opioid switching. No differences in pain and symptom intensity were observed. Opioid escalation index was significantly lower in patients receiving methadone (p<0.0001), although requiring up and down changes in doses. At the doses used, methadone was significantly less expensive (p<0.0001), while the use and costs of supportive drugs and other analgesics were similar in the three groups. No relevant differences in adverse effects were observed among the groups during either the titration phase and chronic treatment.

All the three opioids used as first-line therapy were effective, well tolerated, and required similar amounts of symptomatic drugs or co-analgesics. Methadone was significantly less expensive, but required more changes, up and down, of the doses, suggesting that dose titration of this drug requires major clinical expertise.