"In Europe, methadone is the most commonly prescribed opioid substitute, received by up to three quarters of substitution clients. Buprenorphine-based substitution medications are prescribed to up to a quarter of European substitution clients, and are the principal substitution medications in the Czech Republic, Greece, France, Cyprus, Finland and Sweden (103). The combination buprenorphine-naloxone is available in 15 countries. Treatments with slow-release morphine (Bulgaria, Austria, Slovenia), codeine (Germany, Cyprus) and diacetylmorphine (Belgium, Denmark, Germany, Spain, Netherlands, United Kingdom) represent a small proportion of all treatments."

Source

European Monitoring Centre for Drugs and Drug Addiction, "Annual report 2012: the state of the drugs problem in Europe" (Luxembourg: Publications Office of the European Union, November 2012), Catalog No. TDAC12001ENC, doi:10.2810/64775, p. 76.
http://www.emcdda.europa.eu/p…
http://www.emcdda.europa.eu/a…