Product InformationRegistration Status: Active
SUBUTEX SUBLINGUAL TABLET 8mg is approved to be sold in Singapore with effective from 2000-03-02. It is marketed by ZUELLIG PHARMA PTE LTD, with the registration number of SIN11275P.
This product contains Buprenorphine 8mg in the form of TABLET. It is approved for ORAL use.
This product is manufactured by RECKITT BENCKISER HEALTHCARE (UK) LTD in UNITED KINGDOM.
It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.
Buprenorphine is a derivative of the opioid alkaloid thebaine that is a more potent (25 - 40 times) and longer lasting analgesic than morphine. It appears to act as a partial agonist at mu and kappa opioid receptors and as an antagonist at delta receptors. The lack of delta-agonist activity has been suggested to account for the observation that buprenorphine tolerance may not develop with chronic use.
For the treatment of moderate to severe pain, peri-operative analgesia, and opioid dependence.
Mechanism of Action
Buprenorphine's analgesic effect is due to partial agonist activity at mu-opioid receptors. Buprenorphine is also a kappa-opioid receptor antagonist. The partial agonist activity means that opioid receptor antagonists (e.g., an antidote such as naloxone) only partially reverse the effects of buprenorphine. The binding to the mu and kappa receptors results in hyperpolarization and reduced neuronal excitability. Furthermore, buprenorphine slowly dissociates from its receptor. This observation would account for the longer duration of action compared to morphine, the unpredictability of its reversal by opioid antagonists, and its low level of manifest physical dependence. Its receptor fixation half life is 40 minutes which is significantly longer than morphine (milliseconds).
- 31% bioavailability (sublingual). Sublingual absorption is also dependent on pH. The length of time the tablet is under the tongue has little effect on absorption. Although buprenorphine is rapidly absorbed from the oral mucosa, the absorption into the systemic is slower. The time to reach peak plasma concentration (Tmax) varies between individuals (range of 40 minutes to 3.5 hours). How buprenorphine is formulated does not affect this pharmacokinetic parameter. It also undergoes extensive first-pass metabolism and as a consequence, has very low oral bioavailability. Coadministration with naloxone does not effect the pharmacokinetics of buprenorphine.
- Buprenorphine is very lipophillic and is thus highly distributed. The estimated volume of distribution is 188 - 335 L when given intravenously. It is able to cross into the placenta and breast milk.
- Hepatic. Buprenorphine undergoes both N-dealkylation to norbuprenorphine and glucuronidation. The N-dealkylation pathway is mediated by cytochrome P-450 3A4 isozyme. Norbuprenorphine, an active metabolite and has one-fifth of the pharmacologic activity of the parent compound, can further undergo glucuronidation.
Clearance may be higher in children than in adults. Plasma clearance rate, IV administration, anaesthetized patients = 901.2 ± 39.7 mL/min; Plasma clearance rate, IV administration, healthy subjects = 1042 - 1280 mL/min.
Manifestations of acute overdose include pinpoint pupils, sedation, hypotension, respiratory depression and death.
(−)-buprenorphine | 17-cyclopropylmethyl-4,5α-epoxy-7α-((S)-1-hydroxy-1,2,2-trimethylpropyl)-6-methoxy-6,14-endo-ethanomorphinan-3-ol | 2-(N-cyclopropylmethyl-4,5α-epoxy-3-hydroxy-6-methoxy-6,14-endo-ethanomorphinan-6α-yl)-3,3-dimethyl-2-butanol | 2-[3-cyclopropylmethyl-11-hydroxy-15-methoxy-(14R)-13-oxa-3-azahexacyclo[184.108.40.206,8.01,6.06,14.07,12]icosa-7,9,11-trien-16-yl]-3,3-dimethyl-2-butanol | 21-cyclopropyl-7α-[(S)-1-hydroxy-1,2,2-trimethylpropyl]-6,14-endo-ethano-6,7,8,14-tetrahydrooripavine | Buprenophine | Buprenorfina | Buprenorphinum | Buprenorphine |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.