Health Library Logo

Health Library

What is Varenicline: Uses, Dosage, Side Effects and More

Created at:1/13/2025

Overwhelmed by medical jargon?

August makes it simple. Scan reports, understand symptoms, get guidance you can trust — all in one, available 24x7 for FREE

Loved by 2.5M+ users and 100k+ doctors.

Varenicline is a prescription medication designed to help people quit smoking cigarettes. It works by targeting the same brain receptors that nicotine affects, making cigarettes less satisfying while reducing withdrawal symptoms and cravings.

This medication has helped millions of people break free from tobacco addiction. Understanding how it works and what to expect can help you make informed decisions about your quit-smoking journey.

What is Varenicline?

Varenicline is a smoking cessation medication that acts on your brain's nicotine receptors. It's specifically designed to help adults quit smoking by reducing both the pleasure you get from cigarettes and the uncomfortable withdrawal symptoms.

The medication belongs to a class of drugs called nicotinic receptor partial agonists. Think of it as a gentle substitute that partially fills the same spots in your brain that nicotine usually occupies. This dual action helps break the cycle of addiction while making the transition away from cigarettes more manageable.

Varenicline is available only by prescription and requires careful medical supervision. Your doctor will determine if it's the right choice based on your smoking history, overall health, and other medications you might be taking.

What is Varenicline Used For?

Varenicline is primarily used to help adults quit smoking cigarettes. It's specifically approved for tobacco cessation and works best when combined with counseling and support programs.

The medication is designed for people who are committed to quitting smoking and have tried other methods without success. It's particularly helpful for those who experience strong cravings or severe withdrawal symptoms when attempting to quit.

Some doctors may also prescribe varenicline for other tobacco products, though cigarette smoking remains its primary approved use. The medication is not recommended for casual or social smokers, but rather for those with established nicotine dependence.

How Does Varenicline Work?

Varenicline works by partially activating the nicotine receptors in your brain while simultaneously blocking nicotine from fully binding to these same receptors. This creates a unique two-way effect that makes quitting more achievable.

When you take varenicline, it provides just enough stimulation to reduce withdrawal symptoms like irritability, anxiety, and intense cravings. At the same time, it blocks much of the pleasure and satisfaction you normally get from smoking, making cigarettes less rewarding.

This medication is considered moderately strong in terms of effectiveness. Clinical studies show it can double or triple your chances of successfully quitting compared to willpower alone. However, it's not a magic solution and works best when you're truly committed to quitting.

The blocking effect means that even if you do smoke while taking varenicline, you won't experience the usual rush or satisfaction. This helps break the psychological reward cycle that keeps people addicted to cigarettes.

How Should I Take Varenicline?

Varenicline should be taken exactly as prescribed by your doctor, typically starting one week before your planned quit date. The medication comes in tablet form and is usually taken twice daily with food and a full glass of water.

Your doctor will likely start you on a lower dose for the first few days, then gradually increase it. This helps your body adjust to the medication and reduces the risk of side effects. Taking it with food helps prevent nausea, which is one of the most common side effects.

It's important to eat a regular meal or substantial snack before taking each dose. Avoid taking varenicline on an empty stomach, as this significantly increases the likelihood of feeling nauseous or experiencing stomach upset.

Try to take your doses at the same times each day to maintain steady levels in your system. Many people find it helpful to take one dose with breakfast and another with dinner to establish a routine.

How Long Should I Take Varenicline For?

Most people take varenicline for 12 weeks (about 3 months) as part of their initial quit-smoking plan. Your doctor may recommend a longer course if you've successfully quit but need additional support to maintain your progress.

The typical treatment timeline starts one week before your quit date and continues for 11 more weeks after you stop smoking. Some people may need an additional 12-week course if they've successfully quit but are at high risk of relapsing.

Your doctor will monitor your progress and may adjust the duration based on how well you're responding to treatment. Factors like your smoking history, previous quit attempts, and current stress levels all influence how long you might need the medication.

It's important not to stop taking varenicline suddenly without talking to your doctor, even if you feel you don't need it anymore. Gradual discontinuation helps prevent any potential withdrawal effects from the medication itself.

What Are the Side Effects of Varenicline?

Varenicline can cause side effects, though not everyone experiences them. The most common side effects are generally mild and often improve as your body adjusts to the medication.

Here are the most frequently reported side effects that affect many people taking varenicline:

  • Nausea (affects about 1 in 3 people)
  • Vivid or unusual dreams
  • Headache
  • Difficulty sleeping or insomnia
  • Constipation
  • Gas or bloating
  • Changes in taste
  • Dry mouth

These common side effects are usually manageable and often lessen after the first few weeks of treatment.

Some people experience more concerning side effects that require immediate medical attention. While these are less common, it's important to be aware of them:

  • Mood changes, including depression or anxiety
  • Suicidal thoughts or behaviors
  • Aggressive or violent behavior
  • Severe allergic reactions with rash, swelling, or difficulty breathing
  • Heart rhythm problems or chest pain
  • Seizures (very rare)
  • Sleepwalking or other unusual sleep behaviors

If you experience any of these serious side effects, contact your doctor immediately or seek emergency medical care. Your safety is the top priority, and these effects need prompt medical evaluation.

Who Should Not Take Varenicline?

Varenicline isn't suitable for everyone, and certain people should avoid this medication due to increased risks. Your doctor will carefully evaluate your medical history before prescribing it.

You should not take varenicline if you have a known allergy to the medication or any of its ingredients. People with certain mental health conditions may also need to avoid it or require extra monitoring.

Here are the main groups of people who should use caution or avoid varenicline entirely:

  • People with a history of severe depression or suicidal thoughts
  • Those with bipolar disorder or other serious mental health conditions
  • Individuals with severe kidney disease
  • People who have had seizures or epilepsy
  • Those with a history of heart problems or cardiovascular disease
  • Pregnant or breastfeeding women
  • People under 18 years old

Your doctor will weigh the benefits against the risks for your specific situation. Sometimes the benefits of quitting smoking outweigh the potential risks of taking varenicline, even with certain medical conditions.

Varenicline Brand Names

Varenicline is most commonly known by its brand name Chantix in the United States. This is the original brand name under which the medication was first marketed and is still widely recognized.

In other countries, varenicline may be sold under different brand names, including Champix in Canada, the UK, and many other international markets. The active ingredient remains the same regardless of the brand name.

Generic versions of varenicline are also available in some regions, which contain the same active ingredient but may cost less than the brand-name versions. Your pharmacist can help you understand which version you're receiving.

Varenicline Alternatives

If varenicline isn't right for you, several other FDA-approved medications can help with smoking cessation. Each works differently and may be better suited to your specific needs and medical history.

Nicotine replacement therapy is often the first alternative people try. This includes patches, gum, lozenges, nasal sprays, and inhalers that provide controlled amounts of nicotine without the harmful chemicals in cigarettes.

Bupropion (Zyban) is another prescription medication that can help with smoking cessation. It's an antidepressant that also reduces nicotine cravings and withdrawal symptoms, though it works through a different mechanism than varenicline.

Non-medication approaches like counseling, support groups, behavioral therapy, and mobile apps can also be effective, either alone or combined with medication. Many people find success with a combination of methods rather than relying on just one approach.

Is Varenicline Better Than Nicotine Replacement Therapy?

Varenicline has been shown to be more effective than nicotine replacement therapy in clinical studies. Research indicates that varenicline can help about 20-25% of people quit smoking long-term, compared to 10-15% with nicotine patches or gum.

However, "better" depends on your individual circumstances and tolerance for side effects. Some people do very well with nicotine replacement therapy and prefer it because it has fewer potential side effects than varenicline.

Nicotine replacement therapy is often easier to obtain since many forms are available over-the-counter. It's also generally considered safer for people with certain medical conditions or mental health concerns.

The best choice for you depends on your smoking history, previous quit attempts, medical conditions, and personal preferences. Your doctor can help you weigh the pros and cons of each option based on your specific situation.

Frequently asked questions about Varenicline (oral route)

People with heart disease need extra caution when considering varenicline. Some studies have suggested a possible small increase in cardiovascular events, though the evidence is not conclusive.

Your cardiologist and primary care doctor should work together to evaluate whether varenicline is safe for you. They'll consider your specific type of heart condition, how well-controlled it is, and your overall cardiovascular risk.

For many people with heart disease, the benefits of quitting smoking far outweigh the potential risks of taking varenicline. Smoking itself is one of the worst things you can do for your heart, so successful cessation usually provides significant cardiovascular benefits.

If you accidentally take more varenicline than prescribed, contact your doctor or poison control center immediately. Taking too much can increase the risk of serious side effects like seizures or heart rhythm problems.

Don't wait to see if you feel okay. Even if you don't notice immediate symptoms, an overdose can still be dangerous. Call the Poison Control Center at 1-800-222-1222 or seek emergency medical care right away.

Try to have the medication bottle with you when you call or go to the hospital. This helps medical professionals know exactly how much you took and when, which is important for proper treatment.

If you miss a dose of varenicline, take it as soon as you remember, unless it's almost time for your next scheduled dose. In that case, skip the missed dose and continue with your regular schedule.

Never take two doses at once to make up for a missed dose. This can increase your risk of side effects without providing additional benefits for smoking cessation.

If you frequently forget doses, try setting phone reminders or using a pill organizer. Consistent dosing is important for varenicline to work effectively, so establishing a routine helps ensure success.

You should complete the full course of varenicline as prescribed by your doctor, even if you feel you no longer need it. Most people take it for 12 weeks, and stopping early may increase your risk of starting smoking again.

If you're experiencing intolerable side effects, talk to your doctor before stopping. They may be able to adjust your dose or suggest ways to manage the side effects rather than discontinuing the medication entirely.

Some people benefit from a gradual reduction in dose rather than stopping abruptly. Your doctor will advise you on the best approach for discontinuing varenicline based on your progress and individual circumstances.

You should be very cautious about drinking alcohol while taking varenicline. Some people experience increased alcohol sensitivity, meaning they feel intoxicated more quickly or intensely than usual.

Alcohol can also worsen some of varenicline's side effects, particularly nausea and dizziness. Additionally, drinking alcohol might make it harder to stick to your quit-smoking plan.

If you choose to drink, do so in moderation and pay close attention to how you feel. Many people find it helpful to avoid alcohol entirely during their quit-smoking journey to give themselves the best chance of success.

Want a 1:1 answer for your situation?

Ask your question privately on August, your 24/7 personal AI health assistant.

Loved by 2.5M+ users and 100k+ doctors.

footer.address

footer.talkToAugust

footer.disclaimer

footer.madeInIndia