What is buprenorphine?
Buprenorhine is an opioid partial agonist/antagonist which attaches itself to the micro and k receptors of the brain. Its activity in opioid maintenance treatment is attributed to its slowly reversible link with the micro receptors which, over a prolonged period, minimizes the need of the addicted patient for drugs.
Buprenorphine as a wide margin of safety due to its partial agonist/antagonist activity, which limits its depressant effects, particularly on cardiac and respiratory functions.
Absorption can take place through the buccal mucosa following sublingual administration and peak plasma concentrations are achieved after 90 minutes. The absorption of buprenorphine is followed by a rapid distribution phase and a half-life of 2 to 5 hours. Buprenorphine is about 96% bound to plasma proteins. Plasma elimination half-lives have ranged from 1.2 to 7.2 hours.
Buprenorphine is oxidatively metabolised by 14-N-dealkylation to N-desalkyl-buprenorphine (also known as norbuprenorphine) via cytochrome P450 CY3A4 and by glucuroconjugation of the parent molecule and the dealkylated metabolite. Norbuprenorphine is a µ (mu) agonist with weak intrinsic activity.
Elimination of buprenorphine is bi- or tri-exponential, with a long terminal elimination phase of 20 to 25 hours, due in part to reabsorption of buprenorphine after intestinal hydrolysis of the conjugated derivative, and in part to the highly lipophilic nature of the molecule. Buprenorphine is essentially eliminated in the faeces by biliary excretion of the glucuroconjugated metabolites (80%), the rest being eliminated in the urine.
-white, round, 6.5 mm in diameter biconvex uncoated tablets with "8" embossed on one side.
DOSAGE & ADMINISTRATION