Chantix

Introduction

Written by Patricia Weiser, PharmD
Medically reviewed by Rosanna Sutherby, PharmD
Updated on August 31, 2023

Varenicline (var EN i kleen) is a generic medication prescribed for smoking cessation. It’s taken to help people quit smoking. Varenicline belongs to a group of drugs called nicotinic receptor partial agonists.

This article doesn’t provide coupons for all forms of varenicline. To find coupons for varenicline’s starting month box, see this article.

Side effects of varenicline

Varenicline may cause mild or serious side effects. More common mild side effects of varenicline and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.

To learn more about varenicline’s side effects, ask your doctor or pharmacist. You can also refer to the prescribing information for varenicline listed in the “Resources” section.

Mild side effects

More common mild side effects reported with varenicline are listed below.

This article doesn’t include all possible mild side effects of the drug. To learn more about varenicline’s side effects, refer to the prescribing information for varenicline listed in the “Resources” section.

With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.

Varenicline oral tablet’s mild side effects include:

• nausea
• dreams or nightmares that are unusual, strange, or vivid
• constipation
• gas
• mild allergic reaction*

* For details about this side effect, see the “Interactions and warnings for varenicline” section.

Serious side effects

Serious side effects of varenicline are listed below.

This article doesn’t include all possible serious side effects of the drug. To learn more about varenicline’s side effects, refer to the prescribing information for varenicline listed in the “Resources” section.

With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.

In general, varenicline’s serious side effects include:

• seizures
• dizziness, which may lead to accidental injury or make driving unsafe
• vision or hearing problems
• depression
• anxiety
• agitation
• mania* (periods of unusually high energy)
• hallucinations* (seeing or hearing things that aren’t real)
• suicidal thoughts or behaviors*
• sleepwalking*
• severe allergic reaction†

* These side effects weren’t reported in studies of varenicline. But they’ve occurred in people after the drug was approved for use.
† For details about this side effect, see the “Interactions and warnings for varenicline” section.

Suicide prevention

If you or someone you know is in crisis and considering suicide or self-harm, please seek support:

• Call the 988 Suicide and Crisis Lifeline at 988.
• Text HOME to the Crisis Textline at 741741.
• Not in the United States? Find a helpline in your country with Befrienders Worldwide.
• Call 911 or your local emergency services number if you feel safe to do so.

If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.

If you are not in the same household, stay on the phone with them until help arrives.

Interactions and warnings for varenicline

Below, you’ll find information about varenicline’s possible interactions and warnings.

Interactions of varenicline

Certain things may affect how a drug works. These include getting vaccines, consuming alcohol* or certain foods, or taking the drug with other medications. This effect is called a drug interaction.

Before you take varenicline, ask your doctor to check for possible interactions. Be sure to tell them about any of the following you take or use:

• prescription or over-the-counter drugs
• vitamins, herbs, or supplements

To learn about drug-condition interactions, see the “Warnings for varenicline” section below.

* If you drink alcohol, it’s recommended that you do not consume it while taking varenicline. Talk with your doctor if you have concerns about avoiding alcohol during varenicline treatment.

Warnings for varenicline

Some people should not take varenicline, and others should take it cautiously.

Varenicline could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether varenicline is a safe option for you.

Ask your doctor about specific warnings for varenicline, and be sure to tell your doctor about your:

• current health, including any allergies to medications
• past health conditions or surgeries

Allergic reaction

Varenicline can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.

If you’ve had an allergic reaction to varenicline or any of its ingredients, your doctor will likely not prescribe varenicline. They can tell you about medications that are safer options for you.

A mild allergic reaction may cause the following symptoms:

• skin rash
• itchiness
• flushing (temporary warmth, redness, or deepening of skin color)

A severe allergic reaction may cause the following symptoms:

• swelling under your skin, usually in your hands, feet, eyelids, or lips
• swelling of your mouth, throat, or tongue, which can cause breathing problems

If you have an allergic reaction to varenicline, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.

Overdose of varenicline

You should not take more varenicline than your doctor prescribes. For some drugs, doing so may lead to harmful effects or overdose.

If you think you’ve taken too much varenicline, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

Pregnancy or breastfeeding and varenicline

Information about varenicline and pregnancy and breastfeeding is described below.

Varenicline and pregnancy

There are risks to taking varenicline during pregnancy. But there are also risks with smoking while pregnant. (Keep in mind that varenicline is prescribed to help people quit smoking.)

If you’re planning a pregnancy or can become pregnant, talk with your doctor about smoking cessation options during pregnancy. Together, you can discuss the risks and benefits of your treatment options and decide whether you should take varenicline during pregnancy.

Varenicline and breastfeeding

It’s not known whether varenicline should be taken while breastfeeding. If you’re breastfeeding or planning to do so, talk with your doctor before taking this medication.

Common questions about varenicline

Below you’ll find answers to a few commonly asked questions about varenicline.

What is varenicline’s mechanism of action? How does the drug work?

Varenicline works by binding to nicotine receptors in your brain. This helps reduce cravings for nicotine. Varenicline helps you think less about wanting to smoke, which can help you quit.

It usually takes about a week for varenicline to start working. Most people aim to quit smoking 8–35 days after starting varenicline treatment. For some people, it may take up to 3 months of varenicline treatment before they feel ready to quit smoking completely.

If you’d like to know more about what to expect with varenicline treatment, talk with your doctor or pharmacist.

Can you still smoke while taking varenicline?

Yes. It’s common for people to continue smoking while taking varenicline until they’re ready to quit.

Doctors recommend that you commit to quitting smoking on a specific day of your choice, referred to as your “quit date.” Before starting varenicline, you and your doctor will decide which of the following options is right for you:

• Option 1: Set a quit date. Start taking varenicline 1 week before your quit date.
• Option 2: Start taking varenicline, then set a quit date 8–35 days into treatment.
• Option 3: Start taking varenicline. Over the first 4 weeks of treatment, you’ll reduce the number of cigarettes you smoke per day by half. Then, over the next 4 weeks, you’ll reduce this number by half again with a goal of arriving at your quit date by week 12.

Depending on which of these options you choose, your doctor may recommend taking varenicline for a total of 12 or 24 weeks.

If you smoke after your quit date, you can keep taking varenicline and set a new quit date. Talk with your doctor or pharmacist for other resources to help you successfully quit smoking. Assistance is also available by calling the National Network of Tobacco Cessation Quitlines at 800-QUIT-NOW (800-784-8669). Or check out smokefree.gov for additional resources and tips.

Are there any brand names available for varenicline oral tablet?

No. Chantix was the original brand-name version of varenicline oral tablet.

Pfizer, the drugmaker of Chantix, recalled Chantix tablets in 2021. The tablets contained high levels of an impurity called nitrosamine. High levels of nitrosamine may increase the risk of cancer. After the recall, Chantix’s drugmaker stopped making the drug.

Varenicline is currently available as a generic medication. Varenicline tablets may contain nitrosamine. But the level of nitrosamine in a varenicline tablet is low enough that the Food and Drug Administration (FDA) considers it to be acceptable.

For more information about Chantix or varenicline, talk with your doctor or pharmacist.

Uses of varenicline

The Food and Drug Administration (FDA) approves prescription drugs such as varenicline for certain conditions. The approved use for varenicline is described below.

Use for help with smoking cessation

Doctors may prescribe varenicline oral tablet for smoking cessation (to help people quit smoking). It’s used for this purpose in adults and adolescents ages 17 years and older. It’s usually prescribed for 12–24 weeks.

Smoking cessation (quitting smoking) is one of the best changes you can make for your health. But quitting smoking is challenging. This is because cigarettes contain nicotine, a substance that causes cravings and addiction. (Addiction refers to being unable to stop using a substance even though it may be causing harm.) Varenicline works to help your brain reduce cravings for nicotine.

To increase your chances of success, your doctor will recommend additional strategies to help you quit smoking. These may include tips for managing stress, changing habits linked to smoking, and knowing where to find support. Some possible support resources include the National Network of Tobacco Cessation Quitlines at 800-QUIT-NOW (800-784-8669), local support groups, and smokefree.gov.

Doctors don’t recommend varenicline oral tablet for children ages 16 years and younger. The drug wasn’t shown to be effective for smoking cessation in this age group.

What to ask your doctor

Let your doctor know if you have questions about varenicline or would like more details about it.

Here’s a list of some possible questions you may want to ask your doctor:

• Is it safe to use nicotine replacement therapy, such as nicotine patches or gum, while taking varenicline?
• Are there ways to help prevent or reduce the nausea side effect of varenicline?
• Am I at higher risk of having side effects from varenicline compared with other people?
• Could varenicline cause me to miss my menstrual period?

Resources

• Food and Drug Administration. (2021). Control of nitrosamine impurities in human drugs guidance for industry. https://www.fda.gov/media/141720/download
• Food and Drug Administration. (2021). Pfizer expands voluntary nationwide recall to include all lots of CHANTIX® (Varenicline) tablets due to N-nitroso varenicline content [Press release]. https://www.fda.gov/safety/recalls-market-withdrawals-safety-alerts/pfizer-expands-voluntary-nationwide-recall-include-all-lots-chantixr-varenicline-tablets-due-n
• Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm
• Varenicline tablets, for oral use. (2022). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/1d4c9535-f185-4ea3-9140-60c4bb77f736/spl-doc

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.