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Health conditions related to tobacco use claim 8.7 million lives annually worldwide, according to the 2023 WHO global tobacco epidemic report.[1] Even more tragically, 1.3 million of these deaths are among non-smokers exposed to secondhand smoke.[1] In the United States, nicotine addiction alone accounts for 480,000 fatalities each year—more than all other addictions combined.[2]
At the core of this crisis is nicotine addiction. Successful cessation plans often combine behavioral counseling with medications, including nicotine replacement therapies, bupropion, and varenicline.[2] Among these, varenicline stands out as the most effective non-nicotine, FDA-approved medication specifically designed to support smoking cessation.[3]
This guide will look at varenicline, specifically its uses, side effects, and its role in treating nicotine addiction.
- Varenicline is a prescription medication used to aid smoking cessation by partially binding to brain receptors (α4β2 nicotinic acetylcholine receptors), reducing withdrawal symptoms and cravings while also making nicotine less rewarding.
- Clinical studies show that varenicline is more effective than other treatments, like nicotine replacement therapy and bupropion, leading to higher quit rates and sustained abstinence when used as part of a structured quit plan.
- Common side effects include nausea, vivid dreams, and headaches; however, there are rare but serious risks, such as mood changes, cardiovascular events (especially in at-risk individuals), seizures, and severe allergic reactions.
What is varenicline?
Varenicline is a prescription medication used to help people quit smoking. It is not a nicotine product. It not only reduces cravings but also decreases the satisfaction people feel if they smoke during a relapse.[6]
This medication is usually prescribed as part of a structured quit-smoking program. Treatment typically lasts 12 weeks, though an additional 12 weeks may be recommended to strengthen the chances of staying smoke-free.[5]
How varenicline works
Varenicline works by targeting specific receptors in the brain called α4β2 nicotinic acetylcholine receptors, which play a key role in nicotine addiction. Varenicline is termed a “partial agonist,” as it partially binds to these nicotinic receptors, helping to reduce nicotine withdrawal symptoms and cravings. At the same time, because varenicline blocks nicotine from fully activating these brain receptors, it makes smoking less rewarding.[4]
Varenicline effectiveness
Varenicline remains the most effective treatment for nicotine dependence. Clinical research has shown that varenicline is more effective than other quit-smoking aids, such as NRT (like patches or gum) or the medication bupropion.
For instance, one study found that one-year sustained smoking abstinence rates were significantly higher among smokers using varenicline compared to those using combination NRT.[8] Another study found patients prescribed varenicline were more likely to be abstinent up to 4 years after their first prescription than those prescribed NRT.[9]
A recent study from 2025 highlights varenicline's effectiveness in helping people quit smoking for good, no matter how severe their nicotine addiction.[10] It outperforms single-form nicotine replacement therapies (NRT) and placebos in achieving long-term success. These benefits hold across different groups, especially when combined with behavioral support programs.
Dosage and administration: How to use varenicline
Varenicline is a nicotinic receptor partial agonist designed to help people quit smoking. Following the proper dosage schedule and approach increases the likelihood of success and reduces the risk of side effects.
Precautions before taking varenicline
Before starting varenicline, understanding the potential risks and taking necessary precautions are essential. Discuss your medical history and current health status with your healthcare provider, particularly if you:[11]
- Have a history of mental health conditions
- Have a higher risk of seizures
- Have cardiovascular disease
- Use alcohol
- Have had skin or hypersensitivity reactions
- Are pregnant or breastfeeding
- Operate heavy machinery
Dosage forms and usage information
Varenicline tablets are available in 0.5 mg and 1 mg strengths. Below are the guidelines on how to take the medication. Pairing varenicline with educational materials and counseling improves the chances of quitting successfully.
- Starting on varenicline: Begin taking varenicline one week before your planned quit date. Alternatively, you may start varenicline and set a quit date between days 8 and 35 of treatment. [11]
- Dosage schedule: (Days 1–3) Take 0.5 mg once daily; (Days 4–7) Take 0.5 mg twice daily (morning and evening); (Weeks 2–12) Take 1 mg twice daily. [11]
- Extended treatment: After the initial 12 weeks, an additional 12-week course is recommended for those who have successfully quit smoking to maintain long-term abstinence. [11]
- Gradual reduction approach: For patients unable to quit abruptly, begin varenicline and reduce smoking by 50% within the first 4 weeks and reduce smoking by another 50% over the next 4 weeks. Aim for complete abstinence by 12 weeks while continuing varenicline and continue treatment for an additional 12 weeks, totaling 24 weeks.
- Special dosage considerations: For those with severe renal impairment, start with 0.5 mg once daily and increase to 0.5 mg twice daily if tolerated. The maximum dose for patients on hemodialysis is 0.5 mg daily. Check with your healthcare provider to ensure these dosage recommendations are right for you. Or if you experience significant side effects, your healthcare provider may adjust your dose.
Storage and disposal
- Keep varenicline at room temperature (68°F to 77°F or 20°C to 25°C).
- Follow local guidelines to dispose of unused medication safely. Do not flush it down the toilet unless instructed.
- Store in a safe space away from children.
Potential side effects and safety
Like all medications, varenicline has side effects, and there are special precautions to keep in mind before taking varenicline. [7][11]
Common Side Effects:
- Nausea (which is the most common, affecting about 30% of users)
- Trouble sleeping or unusual, vivid dreams
- Constipation, gas, and vomiting [11]
Rare but serious risks:
- Mental health symptoms, like mood swings, feeling depressed, or having thoughts of harming yourself (seek help right away if you feel like hurting yourself)
- Heart problems, especially in people with pre-existing conditions
- Serious allergic reactions (anaphylaxis), like swelling of the face, lips, or throat, or severe skin rashes, like Stevens-Johnson syndrome and erythema multiforme
- Sleepwalking, which sometimes leads to harmful behaviors
- Seizures, particularly in people with a history of seizures [11]
Varenicline interactions
- Alcohol: Varenicline may increase the effects of alcohol, potentially causing unusual or aggressive behavior. [11]
- Other smoking therapies: Using varenicline with NRT or other therapies may increase side effects, like nausea or dizziness. [11]
- Other medications: Quitting smoking can change how some medicines work (e.g., insulin, blood thinners, or asthma medications). Your doctor may need to adjust your dose.[11]
Varenicline overdose
Most instances of overdose have been described in cases of suicide attempts, and overdose outside this context is rare.
Symptoms of overdose:[11]
- Nausea
- Vomiting
- Dizziness
- Abnormal dreams
- Drowsiness
- Agitation or confusion
- Seizures
What to do in case of overdose
If you or someone else has used too much varenicline, get medical help immediately, call 911, or contact a Poison Control center at 800-222-1222.
To prevent an overdose:
- Always take the medication exactly as prescribed.
- Do not take extra doses if you miss one. Instead, resume your regular schedule.
Exploring varenicline treatment with your doctor
Varenicline can help you quit smoking by reducing cravings and making smoking less enjoyable. To maximize your success, speak to your healthcare provider and follow these suggestions:
- Prepare: Know your smoking habits, list your questions, and research varenicline.
- Be honest: Share your goals, challenges, and any past quit attempts with your provider.
- Ask about options: Discuss combining varenicline with other therapies or support programs.
- Follow through: Take varenicline as prescribed, set a quit date, and stay in touch with your provider to adjust the plan if needed.
A clear conversation with your provider can boost your chances of quitting successfully.
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