bup, bupe, B

Buprenorphine is taken by dissolving a tablet of the drug under the tongue. It activates the opioid receptors in the brain to a lesser extent than methadone, but it acts at the same time to block the receptors, preventing heroin and other opioids from having much effect. Substances that activate receptors in the brain are called ‘agonists’ and those that block these affects are called ‘antagonists’. Buprenorphine is classified as a mixed opioid agonist-antagonist. The action it has on the brain means it has a ‘ceiling effect’ and does not increase potency after a certain dose, unlike heroin and methadone. This means the risk of overdose with buprenorphine is lower than with methadone. It must be prescribed at doses high enough to maintain people in treatment, and should be accompanied by appropriate psychological and social support. It has a similar effectiveness to methadone in terms of retention in treatment and reducing illegal drug use. 

Newer forms of treatment usually involve buprenorphine in combination with naloxone. Naloxone is the opioid antagonist administered at overdose to reverse the effects of opioids. The aim of combining it with buprenorphine is to prevent injecting, with the naloxone only being activated if the substance is injected.