Chantix (Varenicline) – Oral

What Is Chantix?

Chantix (varenicline) is a prescription medication used to aid smoking cessation (the process of quitting smoking) in adults. When used with lifestyle and behavioral modifications, Chantix can help you stop smoking.

The maker of Chantix voluntarily recalled this product in September 2021 after the Food and Drug Administration (FDA) found unacceptable levels of nitrosamines in this medication. Nitrosamines are organic compounds that have the potential to increase the risk of cancer if ingested over a long time. Nitrosamines are also found commonly in water and foods, including cured and grilled meats, dairy products, and vegetables. Although Chantix contains low levels of nitrosamines, it is still above the FDA's acceptable intake limit.

However, if a person is already taking Chantix, they can continue using the medication if the benefits of smoking cessation outweigh the risks associated with these low levels of nitrosamine contamination. Discuss a treatment plan moving forward with your healthcare provider.

Chantix is a selective partial agonist of the nicotinic acetylcholine receptor. It targets and attaches to nicotine receptors in the brain to block nicotine from reaching them. It inhibits dopaminergic activation produced by smoking and decreases the craving, which helps make quitting easier. Chantix also reduces the symptoms of smoking withdrawal.

Varenicline is also available as a nasal spray to treat dry eye.

This article discusses the oral form of varenicline. Chantix is available as tablets to take by mouth.

Drug Facts

Generic Name: Varenicline

Brand Name(s): Chantix

Administration Route(s): Oral

Drug Availability: Prescription

Therapeutic Classification: Smoking cessation agent

Available Generically: Yes

Controlled Substance: N/A

Active Ingredient: Varenicline

Dosage Form(s): Tablet

What Is Chantix Used For?

Chantix is a smoking cessation aid used along with education, behavior modification, and counseling support to help you stop smoking. Tobacco products contain nicotine, which is a highly addictive substance. Quitting smoking can be difficult because of the nicotine withdrawal effects. Chantix helps to reduce the symptoms of nicotine withdrawal and eases the urge to smoke.

Although Chantix was recalled, the FDA reminds people to continue taking their medication until they can receive a replacement treatment. According to the FDA, the health benefits of stopping smoking outweigh the risks from nitrosamine contamination in Chantix.

Chantix (Varenicline) Drug Information - Illustration by Dennis Madamba

Verywell / Dennis Madamba

How to Take Chantix

Read your prescription before starting the medicine. If you do not understand the directions, ask your healthcare provider.

When starting Chantix, you will take it once daily and then switch to twice-a-day dosing, once in the morning and once in the evening. Try to take it around the same time every day. Take the tablets with a glass of water after a meal. 

There are three different ways to take Chantix, which are:

1. Start Chantix One Week Before Quitting

Set a date to quit smoking and start taking Chantix one week before that date. You may smoke during this first week, but try to stop smoking on the quit date. Your dose will be slowly increased to reduce the chance of side effects. Take the dose as prescribed by your healthcare provider twice a day for the rest of the treatment duration.

If you decide to take Chantix this way, you will start with 0.5 milligram (mg) by mouth daily from days one to three, then 0.5 mg twice daily on days four to seven. On day eight and moving forward, take 1 mg twice daily until treatment completion (usually 12–24 weeks).

2. Pick a Quit Date During Treatment

After beginning Chantix, choose to quit smoking anytime between days eight and 35. Continue taking the prescribed dose for the rest of the treatment period.

3. Gradually Reduce Smoking Over Treatment Period

If you are unable or do not want to quit smoking suddenly, your provider may direct you to start taking the tablets and gradually reduce smoking over 12 weeks of treatment to stop by the end of treatment. You can try to smoke only half as many of your average number of cigarettes each day for the first four weeks.

For weeks five through eight, try to smoke only one-quarter of your starting daily number of cigarettes. For the last four weeks (nine through 12), try to smoke even fewer cigarettes or not smoke at all.

It may take several weeks to feel the full benefit of Chantix. You can still quit smoking if you smoke during your treatment when you’re not supposed to. In this case, continue to take Chantix and try not to smoke.

Most people take Chantix for 12 weeks. If you have altogether quit smoking at the end of 12 weeks, you may have to take Chantix for another 12 weeks to prevent you from starting to smoke again.

If you have not stopped smoking after 12 weeks of treatment, talk to your healthcare provider and counselor.

Storage

Store the tablets in a tightly closed container at room temperature (about 77 degrees Fahrenheit), away from heat, direct light, and moisture. Do not keep the tablets in the bathroom. Store all medications locked out of the reach of children.

Make sure to discard expired and unwanted medication properly. Avoid dumping it down the drain, flushing it down the toilet, or throwing it away in a waste bin. The best way to safely get rid of medication is to return it through a medicine take-back program. Consult your pharmacist or local waste disposal company.

How Long Does Chantix Take to Work?

Chantix may need a couple of weeks to work best for some people. Make sure to take it for the full 12 weeks for the best chance at seeing results.

What Are the Side Effects of Chantix?

This is not a complete list of side effects and others may occur. A medical professional can advise you on side effects. If you experience other effects, contact your pharmacist or a medical professional. You may report side effects to the FDA at www.fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Common Chantix side effects may include:

  • Nausea
  • Headache
  • Vomiting
  • Constipation
  • Gas
  • Insomnia (lack of sleep)
  • Unusual dreams.
  • Changes in taste
  • Heartburn
  • Dry mouth
  • Increased or decreased appetite
  • Lack of energy
  • Back, joint, or muscle pain
  • Abnormal menstrual cycles

Many people using Chantix do not have serious side effects. Contact your healthcare provider if any of these side effects persist or make you feel unwell.

Severe Side Effects

Stop taking Chantix and immediately contact your provider if you have any serious side effects, including: 

  • Seizure
  • Heart attack symptoms (such as chest/jaw/left arm pain, shortness of breath, unusual sweating)
  • Symptoms of stroke (sudden weakness on one side of the body, slurred speech, drooping of one side of the face, problems with vision or balance.)
  • Suicidal thoughts
  • Hostile behavior toward yourself, others, or property
  • Aggression
  • Agitation
  • Mood or behavioral changes
  • Depression

Chantix may increase the risk of pancreatitis (inflammation of the pancreas). People taking Chantix should be monitored for abdominal symptoms of pancreatitis, such as:

  • Bloating
  • Tender abdomen
  • Nausea
  • Vomiting
  • Diarrhea
  • Hiccups
  • Indigestion
  • Fever
  • Increased pulse rate
  • Jaundice (yellowing of the skin and whites of the eyes)
  • Clay-colored stools

A severe allergic reaction to Chantix is rare. However, get medical help right away if you feel any symptoms of a severe allergic reaction, including:

  • Rash
  • Blistering and peeling skin
  • Itching
  • Swelling of the face, tongue, or throat
  • Severe dizziness
  • Trouble breathing

Report Side Effects

Chantix may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Chantix Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets):
    • To stop smoking:
      • Adults and children 17 years of age and older—
        • Days 1 to 3: 0.5 milligram (mg) once a day.
        • Days 4 to 7: 0.5 mg 2 times per day.
        • Days 8 to end of treatment: 1 mg 2 times per day.
      • Children 16 years of age and younger—Use is not recommended.

Modifications

In some cases, your healthcare provider may adjust the dose of your medication to optimize treatment.

For example, you may need a dose reduction if you:

  • Have severe renal insufficiency (no dose reduction required for mild to moderate renal impairment)
  • Have a body weight of less than or equal to 121 pounds (55 kilograms)
  • Have intolerable side effects to Chantix

People who show less response to Chantix and require long-term support therapy to prevent relapse may need an increased dose of the medication. Your healthcare provider will work with you to determine the best treatment plan.

Missed Dose

If you forget to take the regular dose of Chantix, take it as soon as possible, or skip the missed dose if it is nearly the time for the next dose. Do not take a double dose to make up for the missed one.

Overdose: What Happens If I Take Too Much Chantix?

Consult with your healthcare provider if you think you've taken too much Chantix.

What Happens If I Overdose on Chantix?

If you think you or someone else may have overdosed on Chantix call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses, has a seizure, has trouble breathing, or can’t wake up after taking too much Chantix, call 911 immediately.

Precautions

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It is very important that your doctor check your or your child's progress at regular visits, especially during the first few weeks that you use this medicine. This will allow for changes in your dose and to help reduce any side effects. Blood and urine tests may also be needed to check for unwanted effects.

This medicine may increase the risk of having a heart attack, especially in patients with heart or blood vessel disease. Call your doctor right away if you have chest pain or discomfort, pain or discomfort in the arms, jaw, back, or neck, pain in your legs when walking, sweating, or troubled breathing.

This medicine may cause some people to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. If you or your caregiver notice any of these side effects, tell your doctor right away.

This medicine may cause serious types of allergic reactions, including angioedema, which can be life-threatening and require immediate medical attention. Tell your doctor right away if you have a rash, itching, a large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals, trouble breathing or swallowing, or chest tightness while you are using this medicine.

Serious skin reactions can occur with this medicine. Check with your doctor right away if you have blistering, peeling, or loosening of the skin, red skin lesions, severe acne or skin rash, sores or ulcers on the skin, or fever or chills while you are using this medicine.

This medicine may cause some people to become drowsy or dizzy, or to have problems with concentration. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Tell your doctor if you have nausea or sleeping problems (trouble sleeping, or unusual dreams) while you are using this medicine. The dose of this medicine may need to be adjusted.

While you are using this medicine be careful to limit the amount of alcohol that you drink.

Sleepwalking may occur while you are using this medicine. This can sometimes lead to a behavior that is harmful to you or other people, or to property. Check with your doctor right away if you start sleepwalking.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take Chantix?

Chantix is a relatively safe drug, but there are certain situations in which you should not take it.

Do not take Chantix if you:

  • Have a severe psychiatric illness and symptoms such as suicidal thoughts
  • Have hypersensitivity reactions or skin reactions, such as Stevens-Johnson syndrome or erythema multiforme, to Chantix
  • Are pregnant or plan to become pregnant

If you have a history of kidney impairment, you may need to take caution when using Chantix. Let your healthcare provider know about your medical history when discussing your treatment options.

Chantix can also increase the effects of alcohol. Try to avoid alcohol or limit consumption while using Chantix.

Moreover, it is not yet established whether Chantix passes through human breastmilk. Talk to your provider if you are breastfeeding.

What Other Medications Interact With Chantix?

Studies have shown no severe drug-drug interactions (two or more drugs that react with each other) with Chantix and other medications. However, it’s good to keep a list of all medications you use (prescription, nonprescription, and herbal products) and consult with your provider before starting the therapy.

After you stop smoking altogether, your provider may need to adjust the doses of certain medicines you take regularly.

What Medications Are Similar?

Zyban (bupropion Hcl Er) is another medication approved by the FDA for smoking cessation. Zyban and Chantix work in different ways and have different side effects. Unlike Chantix, a selective partial agonist of the nicotinic acetylcholine receptor, Zyban is an antidepressant medication.

You and your healthcare provider should determine the most effective medication for you. Your provider may consider your medical condition(s), medical history, and other medications you take.

Frequently Asked Questions

  • What is Chantix used for?

    Chantix is a non-nicotine prescription medicine used with education, behavior modification, and counseling support to help you stop smoking.

  • How is Chantix different from other products?

    Chantix is a non-nicotine pill with a different mechanism of action. It targets nicotine receptors in the brain, attaches to them, and stops nicotine from reaching them.

  • How does Chantix work?

    Chantix blocks the binding of nicotine to receptors in the brain and acts in the same way as nicotine to release small amounts of dopamine and prevent cravings.

  • Can Chantix cause withdrawal symptoms?

    When you try to quit smoking, with or without Chantix, you may feel withdrawal symptoms due to reduced amounts of nicotine, including an urge to smoke, depression or bad mood, and trouble sleeping.

  • How long should I take Chantix?

    Take Chantix for 12 weeks or as prescribed by your healthcare provider. If you have completely quit smoking by 12 weeks, ask your provider if taking it for another 12 weeks may help you remain free of smoking.

  • What are the side effects of Chantix?

    Common side effects of Chantix are: 

    • Headache
    • Nausea and vomiting
    • Change in taste
    • Gas
    • Insomnia
    • Heartburn
    • Change in menstrual cycle
    • Sleep problems, including trouble sleeping and having strange dreams
  • How do I stop taking Chantix?

    Always follow your healthcare provider’s guidelines. Never stop taking this medication on your own.

How Can I Stay Healthy While Taking Chantix?

Smoking continues to be a significant public health problem. Quitting nicotine is challenging, but it can help you become healthier. It can lower your chances of lung disease, heart disease, or getting certain types of cancer related to smoking.

Chantix is a relatively new drug that can help people quit smoking in the short term. Extended use of Chantix can improve self-control outcomes. However, people who are trying to quit smoking also need psychosocial support (considering the influence of both psychological factors and the surrounding environment) at the same time. Therapy with smoking cessation treatments requires professional supervision and a dedicated approach to optimize the chance of success and minimize the adverse effects.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare professional. Consult your doctor before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

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