A composition, in parenteral unit dosage form or in a unit dosage form suitable for delivery via the dermis or mucosa, comprises buprenorphine and an amount of naloxone such that the ratio by weight of buprenorphine to naloxone delivered to or reaching the plasma of a patient is in the range of from 7.5:1 to 12.4:1. The analgesic action of the buprenorphine is potentiated by the low dose of naloxone, which also serves to reduce the likelihood of abuse of the composition by drug addicts. Also provided are a method of treatment of pain and the use of naloxone and buprenorphine for the manufacture of a medicament.