1 INDICATIONS AND USAGE Varenicline tablets are indicated for use as an aid to smoking cessation treatment. Varenicline tablets are a nicotinic receptor partial agonist indicated for use as an aid to smoking cessation treatment. ( 1 and 2.1 )
12.1 Mechanism of Action Varenicline binds with high affinity and selectivity at α4β2 neuronal nicotinic acetylcholine receptors. The efficacy of varenicline in smoking cessation is believed to be the result of varenicline’s activity at α4β2 sub-type of the nicotinic receptor where its binding produces agonist activity, while simultaneously preventing nicotine binding to these receptors. Electrophysiology studies in vitro and neurochemical studies in vivo have shown that varenicline binds to α4β2 neuronal nicotinic acetylcholine receptors and stimulates receptor-mediated activity, but at a significantly lower level than nicotine. Varenicline blocks the ability of nicotine to activate α4β2 receptors and thus to stimulate the central nervous mesolimbic dopamine system, believed to be the neuronal mechanism underlying reinforcement and reward experienced upon smoking. Varenicline is highly selective and binds more potently to α4β2 receptors than to other common nicotinic receptors (>500-fold α3β4, >3,500-fold α7, >20,000-fold α1βγδ), or to non-nicotinic receptors and transporters (>2,000-fold). Varenicline also binds with moderate affinity (Ki = 350 nM) to the 5-HT3 receptor.
2 DOSAGE AND ADMINISTRATION Begin varenicline tablets dosing one week before the date set by the patient to stop smoking. Alternatively, the patient can begin varenicline tablets dosing and then quit smoking between days 8 and 35 of treatment. ( 2.1 ) Starting Week: 0.5 mg once daily on days 1 to 3 and 0.5 mg twice daily on days 4 to 7. ( 2.1 ) Continuing Weeks: 1 mg twice daily for a total of 12 weeks. ( 2.1 ) An additional 12 weeks of treatment is recommended for successful quitters to increase likelihood of long-term abstinence. ( 2.1 ) Consider a gradual approach to quitting smoking with varenicline tablets for patients who are sure that they are not able or willing to quit abruptly. Patients should begin varenicline tablets dosing and reduce smoking by 50% from baseline within the first four weeks, by an additional 50% in the next four weeks, and continue reducing with the goal of reaching complete abstinence by 12 weeks. Continue treatment for an additional 12 weeks, for a total of 24 weeks. ( 2.1 ) Severe Renal Impairment (estimated creatinine clearance less than 30 mL/min): Begin with 0.5 mg once daily and titrate to 0.5 mg twice daily. For patients with end-stage renal disease undergoing hemodialysis, a maximum of 0.5 mg daily may be given if tolerated. ( 2.2 ) Consider dose reduction for patients who cannot tolerate adverse effects. ( 2.1 ) Another attempt at treatment is recommended for those who fail to stop smoking or relapse when factors contributing to the failed attempt have been addressed. ( 2.1 ) Provide patients with appropriate educational materials and counseling to support the quit attempt. ( 2.1 ) 2.1 Usual Dosage for Adults Smoking cessation therapies are more likely to succeed for patients who are motivated to stop smoking and who are provided additional advice and support. Provide patients with appropriate educational materials and counseling to support the quit attempt. The patient should set a date to stop smoking. Begin varenicline…
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6 ADVERSE REACTIONS The following serious adverse reactions were reported in postmarketing experience and are discussed in greater detail in other sections of the labeling: Neuropsychiatric Adverse Events including Suicidality [see Warnings and Precautions (5.1) ] Seizures [see Warnings and Precautions (5.2) ] Interaction with Alcohol [see Warnings and Precautions (5.3) ] Accidental Injury [see Warnings and Precautions (5.4) ] Cardiovascular Events [see Warnings and Precautions (5.5) ] Somnambulism [see Warnings and Precautions (5.6) ] Angioedema and Hypersensitivity Reactions [see Warnings and Precautions (5.7) ] Serious Skin Reactions [see Warnings and Precautions (5.8) ] In the placebo-controlled premarketing studies, the most common adverse events associated with varenicline (>5% and twice the rate seen in placebo-treated patients) were nausea, abnormal (vivid, unusual, or strange) dreams, constipation, flatulence, and vomiting. The treatment discontinuation rate due to adverse events in patients dosed with 1 mg twice daily was 12% for varenicline, compared to 10% for placebo in studies of three months’ treatment. In this group, the discontinuation rates that are higher than placebo for the most common adverse events in varenicline-treated patients were as follows: nausea (3% vs. 0.5% for placebo), insomnia (1.2% vs. 1.1% for placebo), and abnormal dreams (0.3% vs. 0.2% for placebo). Smoking cessation, with or without treatment, is associated with nicotine withdrawal symptoms and has also been associated with the exacerbation of underlying psychiatric illness. Most common adverse reactions (>5% and twice the rate seen in placebo-treated patients) were nausea, abnormal (e.g., vivid, unusual, or strange) dreams, constipation, flatulence, and vomiting. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Aurobindo Pharma USA, Inc. at 1-866-850-2876 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are…
4 CONTRAINDICATIONS Varenicline tablets are contraindicated in patients with a known history of serious hypersensitivity reactions or skin reactions to varenicline tablets. History of serious hypersensitivity or skin reactions to varenicline tablets. ( 4 )
7 DRUG INTERACTIONS Based on varenicline characteristics and clinical experience to date, varenicline has no clinically meaningful pharmacokinetic drug interactions [see Clinical Pharmacology (12.3) ]. Other Smoking Cessation Therapies: Safety and efficacy in combination with other smoking cessation therapies has not been established. Coadministration of varenicline and transdermal nicotine resulted in a high rate of discontinuation due to adverse events. ( 7.1 ) Effect of Smoking Cessation on Other Drugs: Pharmacokinetics or pharmacodynamics of certain drugs (e.g., theophylline, warfarin, insulin) may be altered, necessitating dose adjustment. ( 7.2 ) 7.1 Use with Other Drugs for Smoking Cessation Safety and efficacy of varenicline in combination with other smoking cessation therapies have not been studied. Bupropion Varenicline (1 mg twice daily) did not alter the steady-state pharmacokinetics of bupropion (150 mg twice daily) in 46 smokers. The safety of the combination of bupropion and varenicline has not been established. Nicotine replacement therapy (NRT) Although co-administration of varenicline (1 mg twice daily) and transdermal nicotine (21 mg/day) for up to 12 days did not affect nicotine pharmacokinetics, the incidence of nausea, headache, vomiting, dizziness, dyspepsia, and fatigue was greater for the combination than for NRT alone. In this study, eight of twenty-two (36%) patients treated with the combination of varenicline and NRT prematurely discontinued treatment due to adverse events, compared to 1 of 17 (6%) of patients treated with NRT and placebo. 7.2 Effect of Smoking Cessation on Other Drugs Physiological changes resulting from smoking cessation, with or without treatment with varenicline, may alter the pharmacokinetics or pharmacodynamics of certain drugs (e.g., theophylline, warfarin, insulin) for which dosage adjustment may be necessary.
5 WARNINGS AND PRECAUTIONS Neuropsychiatric Adverse Events: Postmarketing reports of serious or clinically significant neuropsychiatric adverse events have included changes in mood (including depression and mania), psychosis, hallucinations, paranoia, delusions, homicidal ideation, aggression, hostility, agitation, anxiety, and panic, as well as suicidal ideation, suicide attempt, and completed suicide. Observe patients attempting to quit smoking with varenicline for the occurrence of such symptoms and instruct them to discontinue varenicline and contact a healthcare provider if they experience such adverse events. ( 5.1 ) Seizures: New or worsening seizures have been observed in patients taking varenicline. Varenicline should be used cautiously in patients with a history of seizures or other factors that can lower the seizure threshold. ( 5.2 ) Interaction with Alcohol: Increased effects of alcohol have been reported. Instruct patients to reduce the amount of alcohol they consume until they know whether varenicline affects them. ( 5.3 ) Accidental Injury: Accidental injuries (e.g., traffic accidents) have been reported. Instruct patients to use caution driving or operating machinery until they know how varenicline may affect them. ( 5.4 ) Cardiovascular Events: Patients with underlying cardiovascular (CV) disease may be at increased risk of CV events; however, these concerns must be balanced with the health benefits of smoking cessation. Instruct patients to notify their healthcare providers of new or worsening CV symptoms and to seek immediate medical attention if they experience signs and symptoms of myocardial infarction (MI) or stroke. ( 5.5 and 6.1 ) Somnambulism: Cases of somnambulism have been reported in patients taking varenicline. Some cases described harmful behavior to self, others, or property. Instruct patients to discontinue varenicline and notify their healthcare provider if they experience somnambulism. ( 5.6 and 6.2 ) Angioedema and…