Chantix (Varenicline) is a drug marketed by Pfizer for the treatment of nicotine addiction. It functions as a selective, competitive partial agonist at α4β2 (alpha-4-beta-2) nAChRs. Competitive partial agonism at the α4β2 receptors decreases the binding of nicotine to these receptors, thereby modulating the release of dopamine in the mesolimbic pathway as triggered by nicotine ingestion.
As a result of dopaminergic modulation in the mesolimbic pathway, Chantix users don’t feel rewarded when they smoke cigarettes and aren’t as susceptible to severe nicotine withdrawal symptoms (e.g. cravings) upon cessation. Research suggests that Chantix is nearly 3-fold as effective as a placebo and more effective than nicotine replacement therapies (NRTs) and other drugs like Zyban (bupropion). Although many people have success using Chantix to quit smoking, others may not find the drug to be an effective intervention.
In some cases, even if the drug is effective, adverse reactions may occur such as: cardiovascular problems, depression, insomnia, nausea, and suicidal thinking – leading users to discontinue treatment. For this reason, many individuals stop using Chantix, only to hope that their nicotine addiction doesn’t resurface. During the days and weeks after stopping treatment, many individuals want to know how long the Chantix stays in their system.
How long does Chantix stay in your system?
If you’ve recently stopped taking this drug, you may experience Chantix withdrawal symptoms – some of which may be difficult to bear. During this time you may be unsure whether you’re experiencing symptoms of discontinuation or lingering side effects from the drug remaining in your system. To determine how long Chantix stays in your system, it is necessary to know its elimination half-life.
The elimination half-life of Chantix is approximately 24 hours, meaning it takes around 1 full day after your last dose to eliminate 50% of the drug from systemic circulation. Based on this information, we can estimate that it’ll remain in systemic circulation for an average of 5.5 days after your last dose. This indicates that you are likely to have the drug completely out of your system within 6 days of discontinuation.
Unlike many drugs that form metabolites with longer half-lives than the parent compound, Chantix remains virtually unchanged and isn’t subject to significant metabolism. Therefore you won’t need to worry about its metabolites lingering in circulation for a longer duration than varenicline itself. In the vast majority of users, average elimination should occur within 5 to 7 days after complete discontinuation.
- Source: https://pubchem.ncbi.nlm.nih.gov/compound/Varenicline
- Source: http://www.ncbi.nlm.nih.gov/pubmed/21053991
- Source: https://books.google.com/books?id=NtdT5maa_pMC
Variables that influence how long Chantix stays in your system
Though most people will have eliminated Chantix from systemic circulation in an average of 5.5 days after their final dose, certain individuals may eliminate it faster/slower than this “average.” In other words, some individuals may clear the drug from their system in under 5 days, while others could take up to 7 days. Slight variations in elimination times of Chantix are usually due to variables such as: renal function, the individual, dosage, and term of administration.
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Renal function
There is some evidence to suggest that renal function may affect how long Chantix stays in your system prior to complete elimination. Individuals with renal impairment exhibit reduced drug clearance, increased systemic exposure, and a prolonged elimination half-life than people with normative renal function. Furthermore, it appears as though degree of renal impairment may directly affect how long the drug remains in your system.
A person with severe renal impairment or failure is likely to retain Chantix for a significantly longer duration than someone with mild forms of impairment. Research suggests that those with severe forms of impairment experience ~2.1-fold greater exposure to the drug than those with healthy kidney function. Individuals with moderate renal impairment experience ~1.5-fold greater exposure than those with normative renal function.
Mild renal impairment isn’t associated with clinically significant increases in Chantix exposure compared to those without impairment. If you have healthy kidney function, you should excrete Chantix at a relatively predictable speed, whereas if you suffer from a severe form of renal impairment, you can expect to retain the drug for a much longer duration before its fully excreted.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/19916991
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Individual factors
Two individuals may take a 1 mg dose of Chantix for 12 weeks and start at the exact same time, yet one person may retain the drug for a longer duration than the other after discontinuation. Differences in systemic elimination are often a result of individual factors such as: a person’s age, body size, and
Age: A person’s age may have a slight effect on how long Chantix stays in their system after they’ve discontinued treatment. Research suggests that clearance of Chantix decreases with old age and is more efficient among younger adults. It is thought that decreased clearance and longer retention of Chantix among elderly patients (ages 65+) may be a result of diminishing renal function.
Many elderly adults experience moderate or potentially severe forms of renal impairment that are unreported or undiagnosed. Impaired renal function is known to prolong the elimination half-life of drugs like Chantix. Overall decreases in physiologic function among elderly individuals may also contribute to a slower elimination of Chantix.
Body weight: Research suggests that the greater a person’s bodyweight, the quicker they’re likely to clear Chantix from circulation. This is likely due to the fact that individuals with high body weights tend to be more massive than those with low body weights, and thus are ingesting less of the drug relative to the size of their systems. Since the standard dose of Chantix is 1 mg, a smaller/lightweight person will have ingested more of the drug relative to the size of their system, resulting in slightly slower clearance.
The degree to which your body weight will affect clearance and elimination of Chantix is not likely as significant as renal function, but may have a subtle impact. Individuals that are at the abnormally heavy or light ends of the body weight spectrum will likely experience increases or decreases in elimination relative to how much they differ from the norm.
Hydration: Due to the fact that Chantix is excreted via the kidneys, urinary flow rate is likely to have some impact on its excretion. Research suggests that high urinary flow rates may expedite drug excretion via the kidneys, whereas low urinary flow rates may prolong excretion. Since the degree to which a person is hydrated can affect urinary flow rate, hydration may have a direct effect on how long Chantix remains in your body prior to excretion.
A person who stays optimally hydrated may be excreting Chantix from their body with efficiency, whereas someone who is dehydrated may retain the drug for a longer duration prior to excretion. Though hydration may not significantly affect Chantix clearance, it may have a minor impact.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/19916991
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Dosage (0.5 mg to 1 mg)
The dosage of Chantix that you took could slightly affect how long it stays in your system after you stop taking it. The greater the amount of Chantix a person ingests, the more “varenicline” they can expect to accumulate within their body throughout treatment. If a person was to stop from taking 1 mg, after 24 hours of stopping they’d still have 0.5 mg in their system.
If a person was only taking 0.5 mg, after 24 hours of stopping they’d have 0.25 mg remaining in their system; this is half the amount of the 1 mg user. This indicates that the lower dose users will have less of the drug remaining in their systems within the first few days of stopping than the high dose users. Furthermore, there is some evidence that repeated administration of Chantix results in its accumulation throughout the body.
If administered at high doses, it is likely to accumulate to a greater extent and reach an increased plasma concentration compared to low doses. Most literature suggests that users are likely to take either 0.5 mg or 1 mg throughout treatment. However, an individual taking a supratherapeutic dose above 1 mg (e.g. 1.5 mg or 2 mg) may retain the drug for a slightly longer duration after discontinuation than someone taking 0.5 mg or even 0.25 mg.
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Term of administration
The duration over which you’ve been taking Chantix may affect how long it stays in your system as well. It takes 4 days to reach steady state concentrations of the drug, meaning the rate of administration and elimination of Chantix are in equilibrium. If you only took a single dose of Chantix or administered the drug for less than 4 days, you may experience a quicker elimination term than someone who has attained a steady state.
Medical literature suggests that Chantix is to be utilized for a term of 12 weeks, followed by another 12-week period if necessary. A person who has used the drug for a term of 24 weeks is likely to have accumulated more of the drug in his/her system than a person who has used the drug for just several weeks. In other words, long-term users could accumulate slightly more Chantix than short-term users.
It is also necessary to realize that long-term users often end up taking higher doses than short-term users as a result of tolerance. To counteract the tolerance, individuals may be instructed to increase their dosages. Each successive dosage increase may have a slight effect towards prolonging the elimination of Chantix.
- Source: http://www.ncbi.nlm.nih.gov/pubmed/19356390
Chantix (Varenicline): Absorption, Distribution, Excretion
Following oral administration of Chantix, its active ingredient “varenicline” is well absorbed and concentrations peak within 3 to 4 hours at around 9.22 ng/ml (at standard doses). Less than 20% of an ingested dose binds to plasma proteins and steady state concentrations are attained after 4 days of consistent administration. Varenicline is minimally metabolized, and therefore its pharmacokinetics aren’t affected by other drugs and/or hepatic impairment.
The elimination half-life of varenicline is an average of 24 hours, but sources suggest that interindividual half-life variation falls within the range of 10 to 58 hours. This indicates that most people will have eliminated the drug from their systems in under 6 days of their final dose. However, others may eliminate varenicline in considerably faster (2.29 days) or slower (13.29 days) times.
Your body excretes varenicline renally through glomerular filtration and active tubular secretion via the OCT2 (organic cationic transporter). Approximately 92% of the drug is excreted within urine, with 81% of the excretion consisting of unchanged varenicline, and less than 10% of minor varenicline metabolites. These metabolites are hypothesized to form via N-carbamoyl glucuronidation (facilitated by UGT2B7 microsomes) and oxidation.
- Source: https://pubchem.ncbi.nlm.nih.gov/compound/Varenicline
- Source: https://books.google.com/books?id=NtdT5maa_pMC
- Source: http://www.medsafe.govt.nz/profs/datasheet/c/Champixtab.pdf
Tips to clear Chantix from your system
If you’ve completely stopped taking Chantix and want to clear it from your system as quickly as possible, it is necessary to realize that your body is capable of detoxifying itself rapidly. In less than a week you can expect Chantix to have been cleared from your system. If you want to ramp up the detoxification, you could consider implementing some strategies listed below. Prior to implementation of these recommendations, be sure to verify their safety and efficacy with your doctor.
- Discontinuation: The first step to getting Chantix out of your system is to discontinue treatment. Discontinuation should be done under medical supervision to minimize potential adverse effects. If you haven’t yet stopped taking this drug, it will remain in your system until you’ve been off of it for about a week.
- Calcium-D-Glucarate: Chantix is eliminated via the kidneys, which may benefit from supplementation with calcium-d-glucarate. This supplement acts as a beta-glucuronidase inhibitor, thereby facilitating elimination of any molecule in a detoxification pathway. Think of it as helping your kidneys rid themselves of cumulative toxins from drugs (and other sources).
- Activated charcoal: A supplement that can help scavenge toxins within your body is activated charcoal. Though this shouldn’t be taken until you’ve been off of Chantix for awhile, activated charcoal adsorbs toxins and other chemicals throughout your body due to its slight electrical charge. It is known that pharmaceutical drugs can provoke increases in endotoxins, and charcoal is thought to mop these up.
- Stay hydrated: You may benefit from staying hydrated after your final dose of Chantix if your goal is to detoxify as quickly as possible. Hydration ramps up your urinary flow rate, which in turn may increase renal clearance speed of drugs like Chantix. Those who are dehydrated or suboptimally hydrated may benefit most from increasing water intake for detoxification. That said, don’t go overboard with drinking water as this could cause water toxicity.
How long has Chantix stayed in your system after stopping?
If you’ve stopped using Chantix, feel free to share a comment regarding how long you believe it stayed in your system after your final dose. Do you think that your body was able to eliminate it in the average amount of time of ~5.5 days? Or do you think that you may have eliminated it at a slower/faster rate based on various individual factors? Realize that most people will have eliminated the drug in less than a week after they’ve discontinued treatment.
From Australia, genuine comment. I was taking Champix for 8 weeks quit for 7 weeks. After my 5th or 6th week in I felt like a came down with the flu really bad. My head hurt my body ached I slept for two days straight or so. Work, come home, and sleep.
That passed but was left with a runny nose and dry lips for the next week. So I’m jumping off them today. I believe these are all side effects of Champix. Chantix to you in USA. Also had the standard weird dreams and I’d snap like a firework at anything.
I’m gonna have to take the rest of this quitting journey on my own.
I started having seizures in my 3rd week of Chantix. I spent the next 3 years with seizure-like episodes, periods of altered mental status, insomnia, irregular heartbeat, now lung cancer. While the drug itself may leave the body quickly, the chemical changes to your body may last for years.
Have been taking Chantix for about 6 years. Just stopped smoking 6 months ago. Stopped taking Chantix about a week ago. Am having terrible headaches. Is this a side effect?