Buprenorphine is a low molecular weight, lipophilic, opioid analgesic. Recently, a transdermal matrix patch formulation of buprenorphine has become available in three dosage strengths designed to release buprenorphine at 35, 52.5 and 70 micro g/h over a 72-hour period. At least satisfactory analgesia with minimal requirement for rescue medication (50% of patients treated with transdermal buprenorphine, in two trials. Furthermore, despite the availability of rescue medication to all patients, those receiving transdermal buprenorphine tended to experience greater pain relief, reduced pain intensity and longer pain-free sleep. Transdermal buprenorphine was generally well tolerated. Systemic adverse events were typical of opioid treatment or were attributable to the underlying disease.