Health Guide

Varenicline (By mouth)

Varenicline (var-EN-i-kleen)

Helps you quit smoking, as part of a support program.

Brand Name(s):

Chantix, Chantix Starting Month Pak

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. Do not use it if you had an allergic reaction to varenicline.

How to Use This Medicine:


  • Take your medicine as directed. Your dose or schedule may need to be changed to find what works best for you.
  • Tell your doctor what date you have set to stop smoking. This medicine needs to be started 1 week before that date.
  • It is best to take this medicine with a full glass of water after you eat.
  • This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.
  • Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Some medicines can affect how varenicline works. Tell your doctor if you are using any of the following:
    • Insulin
    • Theophylline
    • Blood thinner (including warfarin)
  • This medicine can affect your ability to tolerate alcohol. Limit the amount of alcohol that you drink until you know how this medicine affects you.

Warnings While Using This Medicine:

  • Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, heart or blood vessel problems, angina, or a history of heart attack, stroke, depression or mental health problems, or seizures.
  • For some people, this medicine may increase mental or emotional problems. This may lead to thoughts of suicide and violence. Talk with your doctor right away if you have any thought or behavior changes that concern you. Tell your doctor if you or anyone in your family has a history of bipolar disorder or suicide attempts.
  • This medicine may cause the following problems:
    • Increased risk of heart attack or stroke
    • Serious skin reactions
    • Sleepwalking
  • This medicine may cause you to become dizzy or drowsy, or have trouble concentrating. Do not drive or do anything else that could be dangerous until you know this medicine affects you.
  • Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blistering, peeling, red skin rash
  • Chest pain, fast, pounding, or uneven heartbeat
  • Feeling anxious, depressed, restless, or irritable
  • Numbness or weakness on one side of your body, sudden or severe headache, problems with vision, speech, or walking
  • Seeing or hearing things that are not really there
  • Seizures
  • Thoughts of hurting yourself or others, unusual moods or behaviors

If you notice these less serious side effects, talk with your doctor:

  • Headache
  • Nausea, gas
  • Trouble sleeping, unusual dreams, sleepwalking

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 7/4/2018
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