Description: Varenicline is a smoking cessation agent that blocks the pleasurable effects of smoking in the brain and helps to decrease the desire to smoke.


Absorption: Well absorbed from the GI tract. Bioavailability: Approx 90%. Highest concentration in the blood 3 to 4 hours after taking the drug.

Distribution: Plasma protein binding: <20%.

Metabolism: Minimal metabolism.

Excretion: Via urine (approx 92% as unchanged drug, <10% as metabolites). Elimination half-life: Approx 24 hr.


This medication is used in combination with a stop-smoking program (e.g., education materials, support group, counseling) to help you quit smoking.


Should not be given to patients with severe allergic reactions or skin reactions from this drug.

How to use varenicline

  • There are two ways to use varenicline to help you quit smoking. 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.
  • Take this medication by mouth after food and with a full glass of water.

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

Please see Precautions section.

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.

Get medical help right away if you have any very serious side effects, including:

  • chest/jaw/left arm pain,
  • weakness on one side of the body,
  • severe headache,
  • vision changes,
  • confusion,
  • slurred speech,
  • seizure



  • Allergy: Before taking varenicline, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies.
  • Medical history: Before using this medication, tell your doctor or pharmacist if you had: kidney disease (especially kidney dialysis), mental/mood disorders, heart/blood vessel disease (such as coronary artery disease, peripheral vascular disease, stroke), seizure.
  • Alcohol sensitivity: This drug may 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.
  • Neuropsychiatry syndrom and suicidality: This includes changes in mood, psychosis, hallucinations, paranoia, dellusions, homicidal ideation, hostility, agitation, anxiety and panic, as well as suicidal ideation, suicide attempts, and completed suicide. Stop medication if changes in behavior occurs.
  • Angioedema and hypersensitivity reactions: This include swelling of the face, mouth, neck, and extremities.
  • Serious skin reactions: This includes Stevens-Johnson Syndrome and erythema multiforme. Stop administration if any of these manifest.
  • Cardiovascular events: This includes myocardial infarction and stroke.
  • Accidental injury: There have been reports of vehicular accidents in people taking varenicline. Advise patient to caution driving or operating machinery or engaging in other potentially hazardous activities.
  • Nausea: This is most common adverse reaction with varenicline. For patients with intolerable nausea, a dose reduction should be considered.

Pregnancy risk: Category C. During pregnancy, this medication should be used only when clearly needed.

Breastfeeding: It is unknown if this medication passes into breast milk. Consult your doctor before breast-feeding.


  • Some products that may interact with this drug include: nicotine replacement therapy (e.g., patch, gum, nasal spray).
  • Tell your doctor if you take any of the following medications. Some of the drugs that smoking may affect, among others, are: “blood thinners” (e.g., warfarin), insulin, theophylline.


If overdose is suspected, contact a poison control center or emergency room immediately.


Do not share this medication with others.

Laboratory and/or medical tests (e.g., kidney function) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.

Getting regular exercise and maintaining a nutritious diet, along with using educational materials, receiving counseling, and attending support groups, may help you to successfully quit smoking. Consult your doctor for details.

Missed Dose

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 and resume your usual dosing schedule. 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.


Available Brands

  • Champix [ Pfizer ]

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