...want to quite and are wanting more, in depth information on the latest stop smoking drug Chantix:
I put this together for myself intitially (yes, I'm going to be using it). As a chemist I was digging to find the chemical formula and structure if possible. Here you go. Hope I can figure out how to get the images loaded HERE, but if not they're at the last link:
VARENICLINE - Guidance for health professionals on a new prescription-only stop smoking medication ASH, London, November 2006
The neurochemistry of varenicline is complex. It is an α4ß2 nicotinic acetylcholine receptor partial agonist. Being a partial agonist means that is has both a stimulating and a blocking effect on the receptor it is attracted to. It is structurally similar to cytisine, a naturally occurring substance used as a starting point to develop varenicline (1). Cytisine has been licensed as
a stop smoking medication for around forty years in central and eastern Europe. The α 4ß2 receptor subtype is thought to mediate the rewarding properties of nicotine by modulating the release of dopamine in the nucleus accumbens, the so called “pleasure centre” of the brain.
“Agonist” means that when varenicline binds to the nicotinic receptor it has an effect similar to that of nicotine in stimulating the release of dopamine, although varenicline produces a slower, longer lasting and smaller increase in dopamine release than nicotine. Thus it partially mimics the effect of nicotine and this is thought to explain why it reduces craving when smokers abstain and are deprived of nicotine. However varenicline also binds to the
receptor and partially blocks it (hence “partial” agonist), which reduces the binding siteavailability for nicotine, and so results in a weaker response if people smoke while using the drug. Thus the smoker may experience less satisfaction from smoking. And because varenicline has a higher affinity for the α4ß2 nicotinic acetylcholine receptor than nicotine, it
will displace nicotine on the receptor in the same way that carbon monoxide displaces oxygen from haemoglobin, and thus limit the effect of nicotine. Because varenicline doesn’t have as strong an effect as nicotine in releasing dopamine, the addiction potential is likely to be lower
It would appear that nausea is dose related and titration – for example to 0.5 mg daily – appears to reduce the incidence (4) (see on). There were more reports of abnormal dreams in the varenicline group.
Overall around 10% of people on varenicline across the three phase 3 trials stopped using the drug because of adverse effects. In the two main outcome studies (5,6) the incidence of adverse effects emerging during treatment was similar for varenicline, bupropion and placebo. Other adverse effects noted in the SPC (9) included increased appetite, headache, dizziness and fatigue.
No significant drug-drug interactions associated with the use of varenicline have so far been identified, nor do there appear to be any contra-indications. However, because varenicline is excreted almost entirely by the kidney, precautions should be taken with patients who have severe renal impairment.
Varenicline comes in film coated tablets, each tablet containing 0.5mg of varenicline tartrate.
At the end of treatment, discontinuation of varenicline was associated with anincrease in irritability, urge to smoke, depression, and/or insomnia in up to 3% of patients, so the prescriber should inform the patient accordingly and discuss or consider the potential need for dose tapering.
As varenicline is a new drug, it is possible that with greater experience of its use, druginteractions or rare adverse effects may be identified, so we recommend that patients should be encouraged to report potential side effects to health professionals.
Introduction to nAChRs
and
Mechanism of Action
Varenicline binds with high affinity and selectivity at α4β2 nicotinic acetylcholine receptors sub-type. The efficacy of CHANTIX in smoking cessation is believed to be the result of varenicline’s activity at the α4β2 receptor where its binding produces agonist activity, while simultaneously preventing nicotine binding to these receptors.
Varenicline - Ganfyd
chemical formula and info. Varenicline tartrate
Linear Mode
