An analgesic 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 nalmefene such that the ratio by weight of buprenorphine to nalmefene delivered to or reaching the plasma of a patient is in the range 22.6:1 to 40:1. The analgesic action of the buprenorphine is potentiated by the low dose of nalmefene. Also provided are a method of treatment of pain and the use of nalmefene and buprenorphine for the manufacture of a medicament.