By Medically reviewed by hellodoktor

Generic Name: Chantix Brand Name(s): Generics only. No brands available.


What is Chantix® (varenicline) used for?

Chantix® is commonly used to help you quit smoking. To increase your chance of success, use this medication with a stop-smoking program that includes education, support, and counseling.

You can reduce the risk of heart and lung disease, as well as cancer by quitting smoking. Varenicline works by blocking nicotine’s effects in the brain that make you want to smoke.

How should I take Chantix® (varenicline)?

Chantix® can be used in many ways:

  • The first way is to set a date to quit smoking before beginning treatment with this drug. Begin taking varenicline as directed by your doctor, 1 week before the quit date. When you first start taking this medication, take one 0.5-milligram tablet once a day for 3 days, then increase to one 0.5-milligram tablet twice a day for 4 days. The dose is slowly increased to lessen the chance of side effects (such as nausea, unusual dreams). During this first week, it is okay to smoke. Stop smoking on the quit date and begin taking the dose prescribed by your doctor twice a day for the rest of the 12-week treatment period.
  • The second way to use varenicline is to start taking the drug before you choose a date to quit smoking. Start with the 0.5-milligram tablets and increase the dose as directed by your doctor. Pick a date to quit smoking that is between days 8 and 35 of treatment. Stop smoking on the chosen quit date. No matter which way you use varenicline, always follow your doctor’s directions carefully.

Take Chantix® after eating. Take the medicine with a full glass of water.

If you are not able or willing to quit smoking right away, your doctor may prescribe a third way to take varenicline. Follow your doctor’s directions carefully and reduce your smoking as directed.

How do I store Chantix® (varenicline)?

Chantix® is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store Chantix® in the bathroom or the freezer. There may be different brands of Chantix® that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush Chantix® down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Chantix® (varenicline)?

Before using this drug, tell your doctor if:

  • You are pregnant or breastfeeding. This is because, while you are expecting or feeding a baby, you should only take medicines on the recommendation of a doctor.
  • You are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • You have allergy with any of active or inactive ingredients of Chantix® or other medications.
  • You have any other illnesses, disorders, or medical conditions.

You should not use Chantix® if you used it in the past and had:

  • A serious allergic reaction – trouble breathing, swelling in your face (lips, tongue, throat) or neck
  • A serious skin reaction – blisters in your mouth, peeling skin rash

Is it safe during pregnancy or breastfeeding?

There are no adequate studies in women for determining risk when using this medication during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking this medication. This medication is pregnancy risk category C according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk
  • B=No risk in some studies
  • C=There may be some risk
  • D=Positive evidence of risk
  • X=Contraindicated
  • N=Unknown

Side effects

What side effects can occur from Chantix® (varenicline)?

Common side effects may include:

  • Nausea (may persist for several months), vomiting
  • Constipation, gas
  • Sleep problems (insomnia)
  • Unusual dreams

Stop using Chantix® and call your doctor immediately if you have:

  • A seizure
  • Thoughts about suicide or hurting yourself
  • Strange dreams, sleepwalking, trouble sleeping
  • New or worsening mental health problems – mood or behavior changes, depression, agitation, hostility, aggression
  • Heart attack symptoms: chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating
  • Stroke symptoms: sudden numbness or weakness (especially on one side of the body), slurred speech, problems with vision or balance
  • Severe skin reaction: swelling or redness of the skin, blisters in your mouth, or skin rash that spreads and causes blistering and peeling

Get emergency medical help if you have signs of an allergic reaction to Chantix®: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.


What drugs may interact with Chantix® (varenicline)?

Chantix® may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Smoking can affect the way your body removes certain drugs such as insulin, theophylline, warfarin, among others. When you stop smoking, your doses of these drugs may need to be adjusted by your doctor.

Does food or alcohol interact with Chantix® (varenicline)?

Chantix® may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

Varenicline may alter the way you react to alcohol. Some patients treated with varenicline have experienced decreased tolerance to alcohol, including increased drunkenness, unusual or aggressive behavior, or they had no memory of things that happened.

What health conditions may interact with Chantix® (varenicline)?

Chantix® may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.

Health conditions that may interact with this drug are:

  • Neuropsychiatric Events
  • Alcoholism
  • CV Disease
  • Renal Impairment
  • Seizures


The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using medication.

What is the dose of Chantix® (varenicline) for an adult?

For Smoking Cessation:

  • Days 1 to 3: 0.5 mg orally once a day
  • Days 4 to 7: 0.5 mg orally twice a day
  • Days 8 to end of treatment: 1 mg orally twice a day

What is the dose of Chantix® (varenicline) for a child?

The dosage has not been established in pediatric patients. It may be unsafe for your child. It is always important to fully understand the safety of the drug before using. Please consult with your doctor or pharmacist for more information.

How is Chantix® (varenicline) available?

Chantix® is available in the following dosage forms and strengths:

  • Tablet, film coated: varenicline tartrate 0.5mg

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of Chantix®, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: July 31, 2017 | Last Modified: September 12, 2019

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