Varenicline is used by adults to help stop smoking. To increase your chance of success, use this medication with a stop-smoking program that includes education, support, and counseling. Quitting smoking lowers your risk of heart and lung disease, as well as cancer. Varenicline works by blocking nicotine's effects in the brain that make you want to smoke.

Discuss the risks and benefits of this medication, as well as other ways to quit smoking (such as nicotine replacement treatment), with your doctor.

Read the Medication Guide provided by your pharmacist before you start taking varenicline and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

There are different ways to use varenicline. One way is to set a date to quit smoking before beginning treatment with this drug. Begin taking varenicline as directed by your doctor, 1 to 2 weeks before the quit date. 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). It is okay to smoke during this time. Stop smoking on the quit date. Take the dose prescribed by your doctor twice a day for the rest of the treatment period (usually 12 weeks).

Another 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 date you have chosen. Take the dose prescribed by your doctor for the rest of the treatment period.

If you are not able to pick a quit date, your doctor may direct you to start taking this medication and gradually reduce smoking with a goal to quit by the end of your treatment. Follow your doctor's directions carefully and reduce smoking as directed.

If this medication comes in a dosing package, carefully follow the directions on the dosing package. There are two types of dosing packs: a starting pack and a continuing pack, each containing different strengths of this medication. If this medication comes in a bottle, carefully follow your doctor's directions on the prescription label. If you have any questions about how to take this medication, talk to your doctor or pharmacist.

Take this medication by mouth after eating food and with a full glass of water.

The dosage is based on your medical condition and response to treatment.

Do not increase your dose or take this medication more often than prescribed. Your condition will not improve any faster, and your risk of side effects will increase. Do not take more than 1 milligram twice a day.

Take this medication regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day.

Tell your doctor if you continue to smoke after a few weeks of treatment. If you are not able to quit smoking after 12 weeks of treatment, talk to your doctor.

If you are successful and cigarette-free after 12 weeks of treatment, your doctor may recommend another 12 weeks of treatment with varenicline.

See also Precautions section.

Nausea, headache, vomiting, drowsiness, gas, constipation, trouble sleeping, unusual dreams, or changes in taste may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• burning feeling in feet/toes
• unusual pain in the legs when walking

Stop taking varenicline and get medical help right away if you have any very serious side effects, including:

• seizure
• symptoms of a heart attack (such as chest/jaw/left arm pain, shortness of breath, unusual sweating)
• signs of a stroke (such as weakness on one side of the body, trouble speaking, sudden vision changes, confusion)
• harmful behavior to self/others/property

Rarely, varenicline may cause serious mental/mood changes, even after stopping the medication. Drinking alcohol while taking this medication may increase the risk for mental/mood changes. Quitting smoking itself may also cause mental/mood changes. Stop taking varenicline and tell your doctor or pharmacist right away if you have symptoms such as depression/suicidal thoughts, agitation, aggression, or other unusual thoughts or behavior.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking varenicline, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• kidney disease
• mental/mood disorders (such as schizophrenia, bipolar disorder, depression)
• heart/blood vessel disease (such as coronary artery disease, peripheral vascular disease, stroke)
• seizure

This drug may make you dizzy, drowsy, lose consciousness, or make it difficult to concentrate. Alcohol or marijuana (cannabis) can worsen these effects. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Talk to your doctor if you are using marijuana (cannabis).

This drug may also make you more sensitive to alcohol (including increased drunkenness, unusual behavior, and limited or no memory of things that happened). Limit alcoholic beverages. Be aware of how alcohol affects you while taking this medication.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is unknown if this medication passes into breast milk. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines 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. Tell all your doctors and pharmacists that you are quitting smoking and of all the products you take.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Do not share this medication with others.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.