Champix
Use during pregnancy and breastfeeding
Adequate and strictly controlled studies on the safety of Champix during pregnancy have not been conducted, therefore the use of the drug is contraindicated.
It is not known whether varenicline is excreted into breast milk in humans. If it is necessary to use the drug during lactation, breastfeeding should be discontinued.
Use for liver dysfunction
In patients with impaired liver function, no dose adjustment is required.
Use for renal impairment
For patients with mild (estimated creatinine clearance > 50 ml/min and ≤ 80 ml/min) and moderate (estimated creatinine clearance ≥ 30 ml/min and ≤ 50 ml/min) renal impairment, no dose adjustment is required. In case of severe adverse reactions in patients with moderate renal impairment, the dose may be reduced to 1 mg 1 time / day.
For patients with severely impaired renal function (calculated creatinine clearance <30 ml/min), the recommended dose of Champix is 1 mg 1 time/day. Treatment begins with a dose of 500 mcg 1 time / day, which after 3 days is increased to 1 mg 1 time / day. There is insufficient experience with the use of Champix in patients with end-stage kidney disease, so the drug is not recommended in such cases.
Use in children
Contraindication: age under 18 years (insufficient clinical data on the effectiveness and safety of the drug in this age group).
Use in elderly patients
Elderly patients do not require dose adjustment. It should be borne in mind that in this category of patients the likelihood of renal dysfunction is higher, so it is advisable to evaluate it before starting treatment.
special instructions
The effect of quitting smoking on the body
Physiological changes that occur after smoking cessation with or without treatment with Champix® may alter the pharmacokinetics or pharmacodynamics of some drugs that may require dose adjustment (for example, theophylline, warfarin and insulin). Because Smoking induces the CYP1A2 isoenzyme; quitting smoking can lead to an increase in the concentration of substrates of this isoenzyme in the blood plasma.
Neuropsychiatric disorders
During post-marketing use of the drug, there have been reports of neuropsychiatric disorders, including behavioral or thought disorders, anxiety, psychosis, mood swings, aggressive behavior, agitation, depressive mood, suicidal ideation and suicidal behavior in patients attempting to quit smoking with varenicline. Not all patients had stopped smoking at the time of the onset of these symptoms, and not all patients had previously experienced mental disorders.
The physician should explain to patients receiving the drug to quit smoking the possibility of developing neuropsychiatric symptoms and take into account the need for a gradual dose reduction. Patients, their family members, or caregivers should be advised to stop taking Champix® and seek immediate medical attention if behavioral disturbances, agitation, or depressive mood occur, or if suicidal ideation or behavior occurs that has not previously occurred in the patient. . In many cases, after discontinuation of the drug, the listed symptoms disappeared, but sometimes the symptoms persisted. Therefore, continued monitoring of patients is recommended until symptoms resolve. Before starting treatment, it is necessary to find out whether the patient has previously had any mental disorders.
It should also be borne in mind that depressive mood, in rare cases in combination with suicidal thoughts or attempts, may accompany smoking cessation. In addition, the process of quitting smoking, with or without pharmacotherapy, is usually associated with exacerbations of existing mental disorders (eg, depression).
Clinical studies have been conducted on the use of varenicline in patients suffering from major depressive disorder without psychotic symptoms, receiving regular antidepressant therapy and/or in patients who have had a major depressive episode within the last 2 years and the therapy was successful. According to the results of assessing the patients' condition on psychiatric scales, there were no differences between the groups of patients receiving varenicline and placebo. There was also no worsening of depression during varenicline therapy in either group of patients.
Cardiovascular diseases
When using the drug Champix® in patients with cardiovascular diseases, there was a slight increase in the incidence of complications of these diseases. Such complications more often developed in patients with existing diseases of the cardiovascular system. Overall and cardiovascular mortality were lower in patients receiving varenicline. Patients taking varenicline should tell their prescribers if new symptoms of cardiovascular disease develop or worsen existing ones. Patients should seek immediate medical attention if symptoms consistent with myocardial infarction or stroke occur.
Use in patients with stable schizophrenia or schizoaffective disorder
There are limited data on the use of varenicline in patients with stable schizophrenia or schizoaffective disorder. Caution should be used when using varenicline in patients with a history of mental illness.
Epilepsy
There is no data on the use of Champix® in patients with epilepsy. While using the drug Champix®, seizures developed (in the absence of a history of seizures). If you have a history of seizures or other conditions that lower the seizure threshold, caution should be exercised when using Champix®.
Completion of therapy
Completion of varenicline treatment in 3% of patients was accompanied by increased irritability, smoking urges, depression and/or insomnia. Patients should be warned about such complications and the possibility of dose reduction should be discussed.
Angioedema and hypersensitivity reactions
There are reports of hypersensitivity reactions, including angioedema, in patients taking varenicline. Clinical symptoms of this complication include swelling of the face, mouth (tongue, lips, gums), neck (larynx and pharynx), and extremities. In addition, there are rare reports of the development of life-threatening angioedema, the treatment of which may require emergency medical intervention due to the risk of impaired respiratory function. Patients should immediately stop taking varenicline and contact their healthcare provider if any symptoms of a hypersensitivity reaction develop.
Severe skin reactions
There have been rare reports of severe life-threatening skin reactions, including Stevens-Johnson syndrome and erythema multiforme, in patients taking varenicline. Because These reactions can be life-threatening; you should stop using Champix® at the first signs of a rash or skin reaction and immediately inform your doctor.
Chronic obstructive pulmonary diseases
When using Champix® in patients with COPD, there were no differences in the safety profile compared to healthy patients.
Impact on the ability to drive vehicles and operate machinery
Champix® may cause dizziness and drowsiness, so patients are advised not to drive, use complex machinery, or perform other potentially hazardous tasks until their individual response to the drug is assessed.
Composition of the drug
The drug Champix (Europe) or Chantix (USA) is a drug to combat smoking. It is produced by the American pharmaceutical company (Pfizer). Champix tablets are produced in the form of capsules with a white coating and marked "CHX 0.5" or with a light blue coating and marked "CHX 1.0"
Each capsule contains 500 mcg or 1 mg of varenicline. The substance was obtained and studied in the Department of Biochemistry. Chemist J. Coe received the Galena Award for it in 2007. Manufacturers claim that Champix is 64.1% effective in combating tobacco addiction. Feedback from smokers shows that the claim is justified.
Review of smokers' reviews
Smokers who have used Champix capsules give positive reviews. Most of them managed to get rid of nicotine addiction. People are even willing to overpay for this drug, knowing its effectiveness. Some common points can be noted in the reviews of former smokers:
- the desire to smoke decreased on days 4-5;
- in the second week, complete cessation of cigarettes occurs;
- the desire to smoke arises, but quickly passes;
- Nausea (sometimes vomiting) occurs, which goes away 2 hours after taking the pill, sometimes the nausea is relieved by a small portion of food;
- vivid, memorable dreams appear;
- apathy and suicidal thoughts occur;
- 1-2 packs are enough, depending on smoking experience.
Heavy smokers note that the physiological nicotine addiction quickly passes. It is more difficult to cope with the habit of reaching for a cigarette for any reason. It is necessary to find some distracting techniques. The general opinion of most smokers is that Champix is the best drug in the fight against tobacco addiction.
How do the pills work?
Varenicline, the active ingredient in the smoking cessation drug Champix, interacts with the brain's α4β2 receptors. It activates their biological response. Nicotine also affects these receptors, producing a response in the form of pleasure and forming addiction in smokers.
Nicotine and varenicline are antagonist substances (rivals). Having a greater affinity for α4β2, Champix partially blocks the receptors. Nicotine can no longer interact with them fully. As a result, according to smokers, the pleasure from the process of smoking decreases, the desire to take a cigarette disappears, and the addiction is destroyed.
The instructions for Champix include taking the drug orally with water.
Anti-smoking tablets Champix stop the effect of reinforcement, the essence of which is that when the brain records satisfaction and pleasant sensations, it reinforces a characteristic reaction to their source. The smoker's reaction is already formed in anticipation of enjoying the cigarette. If the expected pleasure does not occur, the reinforcement effect for the smoker does not work.
Pharmacokinetics of oral administration of the anti-smoking drug Champix:
- varenicline is completely absorbed, its maximum in the blood plasma is recorded after 4 hours;
- the ratio of taking the medicine with food and time of day does not affect its bioavailability in the body;
- pharmacokinetics are the same in smokers of any age, gender and race, it does not depend on concomitant treatment, the condition of the liver and lungs, or the degree of tobacco addiction;
- 92% of the dose is evacuated unchanged by the kidneys, the rest in the form of metabolites, the half-life is 24 hours.
Comparative trials of groups of smokers taking anti-smoking pills Champix and placebo showed evidence of a decrease in nicotine addiction after 12 weeks to a greater extent in the first group than in the second.
What do the statistics say?
Constant sociological research and surveys indicate disappointing facts. In all countries of the world, the number of men who smoke is 50%. And the proportion of women who smoke varies from 10% to 50%. That's a lot. Almost half of the world's population is in the grip of nicotine. That’s why anti-smoking pills “Champix” are so relevant today. After all, almost 70% of smokers, having realized the harm of nicotine, strive to quit smoking. But not everyone succeeds, only 5%. And it’s not even a matter of willpower, although it can also play a major role in your quest to start a healthy lifestyle. But one more factor must be taken into account. Nicotine is no less addictive than drugs. For example, cocaine or heroin. And a person is not always able to cope on his own, as dramatic changes occur in the body. And this is where Champix anti-smoking tablets come to the rescue. Do they help? Reviews indicate that the desired effect has been achieved. But what explains the effectiveness of the drug?
pharmachologic effect
A drug for the treatment of nicotine addiction. Varenicline binds with high affinity and selectivity to α4β2 n-cholinergic receptors, for which it is a partial agonist of nicotine, i.e. simultaneously exhibits agonistic activity (but to a lesser extent than nicotine) and antagonism in the presence of nicotine.
The effectiveness of varenicline as a treatment for nicotine addiction is due to its partial agonism at α4β2 nicotinic receptors, binding to which reduces the craving for smoking and facilitates the manifestation of withdrawal syndrome (agonistic activity) and at the same time leads to a decrease in the feeling of pleasure from smoking (antagonism in the presence of nicotine).
In vitro electrophysiological studies and in vivo neurobiochemical studies have shown that varenicline binds to and stimulates α4β2 n-cholinergic receptors, but to a much lesser extent than nicotine. Nicotine competitively binds to the same receptor site for which varenicline has a higher affinity.
Thus, varenicline effectively blocks the ability of nicotine to stimulate α4β2 receptors and activate the mesolimbic dopamine system, a neuronal mechanism that underlies the mechanisms of formation of nicotine addiction (getting pleasure from smoking).
Contraindications
Smokers who have decided to give up their bad habit should not be afraid of the drug Champix: the contraindications to it are few and standards. These are individual intolerance to the drug, expecting a child, breastfeeding. Patient reviews show that cases of incompatibility with the drug are very rare. The effect of the medicine on the fetus has not been studied; reviews from women and doctors have not been recorded.
Champix tablets are contraindicated for use by children and adolescents, because have not been studied for tolerability.
