Although the synthetic opioid buprenorphine has been available clinically for 
almost 30 years, its use has only recently become much more widespread for the 
treatment of opioid addiction. The pharmacodynamic and pharmacokinetic profiles 
of buprenorphine make it unique in the armamentarium of drugs for the treatment 
of opioid addiction. Buprenorphine has partial mu-opioid receptor agonist 
activity and is a kappa-opioid receptor antagonist; hence, it can substitute for 
other micro-opioid receptor agonists, yet is less apt to produce overdose 
reactions or dysphoria. On the other hand, buprenorphine can block the effects 
of opioids such as heroin (diamorphine) and morphine, and can even precipitate 
withdrawal in individuals physically dependent upon these drugs. Buprenorphine 
has significant sublingual bioavailability and a long half-life, making 
administration on a less than daily basis possible. Furthermore, its 
discontinuation is associated with only a mild withdrawal syndrome. Clinical 
trials have demonstrated that sublingual buprenorphine is effective in both 
maintenance therapy and detoxification of individuals addicted to opioids. The 
introduction of a sublingual formulation combining naloxone with buprenorphine 
further reduces the risk of diversion to illicit intravenous use. Because of its 
relative safety and lower risk of illegal diversion, buprenorphine has been made 
available in several countries for treating opioid addiction in the private 
office setting, greatly enhancing treatment options for this condition.