Nicholson, A.B. (2006). Methadone for cancer pain [Cochrane review]. In The Cochrane Library, Volume 4, 2006. Oxford, UK: Update Software.
To determine the effectiveness and safety of methadone analgesia in patients with cancer pain; to assess the adverse effects associated with methadone analgesia for the treatment of cancer pain
Evidence suggests that methadone is an analgesic with an efficacy similar to that of morphine and with side effects that are similar to those of morphine. Although methadone is similar to morphine, the pharmacokinetics and pharmacodynamics of methadone make dose titration difficult. Methadone presents the risk of drug accumulation to toxic levels. There is a significant danger that the effect of methadone accumulation leading to delayed onset of adverse effects has not been represented. The majority of studies involved were single-dose comparisons or pertained to short-term use. Such comparisons fail to reproduce clinical practice; such studies do not reveal delayed adverse effects. One study, which compared methadone to morphine over 28 days, reported an increased rate of withdrawal from the methadone group. Withdrawal was due to side effects. Author drew no conclusion regarding the relative merits, in the management of various pain syndromes, of methadone compared to those of other opioids. The additional study found methadone to be as effective as morphine in the treatment of neuropathic pain, but not superior to morphine.
Few studies presented complete data sets regarding pain. No meta-analysis was possible.