ATC Group: N07BC Drugs used in opioid dependence

Buprenorphine is an opioid partial agonist/antagonist which attaches itself to the μ (mu) and κ (kappa) receptors of the brain. Its activity in opioid maintenance treatment is attributed to its slowly reversible link with the μ receptors which, over a prolonged period, minimises the need of illicit opioids for patients with opioid dependence.

Levomethadone is a fully synthetic opioid analgesic which, as a basic diphenylmethane derivative, can be structurally derived from morphine. Bradycardia, hypotension, bronchoconstriction and antidiuresis are among the pharmacological effects of levomethadone, in addition to other classical opioid effects such as sedation, euphoria and miosis.

Lofexidine is a central alpha-2 adrenergic agonist that binds to receptors on adrenergic neurons. This reduces the release of norepinephrine and decreases sympathetic tone. It is used for mitigation of opioid withdrawal symptoms to facilitate abrupt opioid discontinuation in adults.

Methadone is a synthetic opioid analgesic similar to morphine although less sedative. It acts on the CNS system and smooth muscles via the peripheral nervous system.