Varenicline Uses, Dosage, Side Effects, Food Interaction and all others data.

Varenicline binds with high affinity and selectivity at α4β2 neuronal nicotinic acetylcholinereceptors. The efficacy of Varenicline in smoking cessation is believed to be the result of varenicline's activity at α4β2 sub-type of the nicotinic receptor where its binding produces agonist activity, while simultaneously preventing nicotine binding to these receptors.Electrophysiology studies in vitro and neurochemical studies in vivo have shown that varenicline binds to α4β2 neuronal nicotinic acetylcholine receptors and stimulates receptor-mediated activity, but at a significantly lower level than nicotine. Varenicline blocks the ability of nicotine to activate α4β2 receptors and thus to stimulate the central nervous mesolimbic dopamine system, believed to be the neuronal mechanism underlying reinforcement and reward experienced upon smoking. Varenicline is highly selective and binds more potently to α4β2 receptors than to other common nicotinic receptors ( >500-fold α3β4, >3,500fold α7, >20,000-fold α1βγδ), or to non-nicotinic receptors and transporters (> 2,000-fold). Varenicline also binds with moderate affinity (Ki = 350 nM) to the 5-HT3 receptor.

Varenicline is a partial nicotinic acetylcholine receptor agonist, designed to partially activate this system while displacing nicotine at its sites of action in the brain.

Trade Name Varenicline
Availability Prescription only
Generic Varenicline
Varenicline Other Names Vareniclina, Varenicline, Vareniclinum
Related Drugs Xiidra, bupropion, cyclosporine ophthalmic, Chantix, Restasis, nicotine, Systane, Artificial Tears, Zyban, Nicoderm CQ
Weight 0.5mg, 0.5mg + 1mg, 1mg
Type Oral tablet
Formula C13H13N3
Weight Average: 211.268
Monoisotopic: 211.110947431
Protein binding

Less than 20%.

Groups Approved, Investigational
Therapeutic Class Drugs used in substance dependence
Available Country United States
Last Updated: September 19, 2023 at 7:00 am


Varenicline is used for use as an aid to smoking cessation treatment.

Varenicline is also used to associated treatment for these conditions: Cessation, Smoking

How Varenicline works

Varenicline is an alpha-4 beta-2 neuronal nicotinic acetylcholine receptor partial agonist. The drug shows high selectivity for this receptor subclass, relative to other nicotinic receptors (>500-fold alpha-3 beta-4, >3500-fold alpha-7, >20,000-fold alpha-1 beta gamma delta) or non-nicotinic receptors and transporters (>2000-fold). The drug competitively inhibits the ability of nicotine to bind to and activate the alpha-4 beta-2 receptor. The drug exerts mild agonistic activity at this site, though at a level much lower than nicotine; it is presumed that this activation eases withdrawal symptoms.


Varenicline dosage

Smoking cessation therapies are more likely to succeed for patients who are motivated to stop smoking and who are provided additional advice and support. Provide patients with appropriate educational materials and counseling to support the quit attempt.The patient should set a date to stop smoking. Begin Varenicline dosing one week before this date. Alternatively, the patient can begin Varenicline dosing and then quit smoking between days 8 and 35 of treatment.The recommended dose of Varenicline is 1 mg twice daily following a 1-week titration as follows:

  • Days 1-3: 0.5 mg once daily
  • Days 4-7: 0.5 mg twice daily
  • Day 8-end of treatment: 1 mg twice daily

Patients should be treated with Varenicline for 12 weeks. For patients who have successfully stopped smoking at the end of 12 weeks, an additional course of 12 weeks treatment with Varenicline is recommended to further increase the likelihood of long-term abstinence.For patients who are sure that they are not able or willing to quit abruptly, consider a gradual approach to quitting smoking with Varenicline. Patients should begin Varenicline dosing and reduce smoking by 50% from baseline within the first four weeks, by an additional 50% in the next four weeks, and continue reducing with the goal of reaching complete abstinence by 12 weeks. Continue Varenicline treatment for an additional 12 weeks, for a total of 24 weeks of treatment. Encourage patients to attempt quitting sooner if they feel readyPatients who are motivated to quit, and who did not succeed in stopping smoking during prior Varenicline therapy for reasons other than intolerability due to adverse events or who relapsed after treatment, should be encouraged to make another attempt with Varenicline once factors contributing to the failed attempt have been identified and addressed.Consider a temporary or permanent dose reduction in patients who cannot tolerate the adverse effects of Varenicline.

Varenicline should be taken orally after eating and with a full glass of water.

Side Effects

Nasopharyngitis, bronchitis, sinusitis, increased wt, decreased &/or increased appetite, abnormal dreams, insomnia, headache, somnolence, dizziness, dysgeusia, dyspnea, cough, nausea, GERD, vomiting, constipation, diarrhea, abdominal distension & pain, toothache, dyspepsia, flatulence, dry mouth, rash, pruritus, arthralgia, myalgia, back pain, chest pain, fatigue, abnormal liver function test.


Discontinue use if changes in behavior or thinking, agitation or depressed mood, anxiety, psychosis, mood swings, aggressive behavior, agitation, depressed mood, suicidal ideation & behavior. Concomitant use in patients attempting to quit smoking. Patients with history of seizures or other conditions that potentially lower seizure threshold. Report if patients had history of psychiatric illness prior to initiation. Hypersensitivity reactions including angioedema, swelling of the face, mouth (tongue, lips, gums), neck (throat & larynx) & extremities. Severe cutaneous reactions including Stevens-Johnson syndrome & erythema multiforme (rare). Special Precautions for Disposal and Other Handling: No special requirements for disposal.


May increase intoxicating effects of alcohol.

Food Interaction

  • Avoid excessive or chronic alcohol consumption. Varenicline may increase the effects of alcohol; therefore, reduce consumption of alcohol when starting varenicline.

[Moderate] GENERALLY AVOID: Varenicline may enhance the effects of alcohol as well as alter the way an individual reacts to alcohol.

During postmarketing use, some patients have reported experiencing increased intoxicating effects of alcohol while taking varenicline.

In addition, some reported cases of neuropsychiatric events, including unusual and sometimes aggressive behavior directed toward oneself or others, may have been worsened by concomitant use of alcohol.

These events were often accompanied by amnesia.

MANAGEMENT: Patients should be advised to limit their consumption of alcohol until they know whether varenicline affects their tolerance for alcohol, and to exercise caution driving or operating machinery until they know how quitting smoking and

Patients should immediately stop taking varenicline and contact their physician if they develop agitation, hostility, aggressive behavior, depressed mood, or changes in behavior or thinking that are not typical for them, or if they develop suicidal ideation or behavior.

Half Life

The elimination half-life of varenicline is approximately 24 hours

Elimination Route

Varenicline undergoes minimal metabolism, with 92% excreted unchanged in the urine. Renal elimination of varenicline is primarily through glomerular filtration along with active tubular secretion possibly via the organic cation transporter, OCT2.

Pregnancy & Breastfeeding use

Use in Pregnancy: Category C. There are no adequate and well-controlled studies in pregnant women. Varenicline should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus 

Use in Lactation: It is unknown whether varenicline is excreted in human breast milk. Animal studies suggest that varenicline is excreted in breast milk. A decision on whether to discontinue breast-feeding or to discontinue therapy with varenicline should be made taking into account the benefit of breast-feeding to the child and the benefit of varenicline therapy to the woman


Known hypersensitivity to varenicline or to any of the excipients in the product (microcrystalline cellulose, dibasic calcium phosphate, anhydrous, croscarmellose sodium, colloidal silicon dioxide, magnesium stearate, Opadry Blue/White and Opadry Clear).

Innovators Monograph

You find simplified version here Varenicline

Varenicline contains Varenicline see full prescribing information from innovator Varenicline Monograph, Varenicline MSDS, Varenicline FDA label


What is Varenicline used for?

Varenicline is used along with education and counseling to help people stop smoking. It works by blocking the pleasant effects of nicotine (from smoking) on the brain.

What are the common side effects of Varenicline?

Varenicline may cause side effects include:

  • nausea
  • constipation
  • diarrhea
  • gas
  • abdominal pain
  • vomiting
  • heartburn
  • bad taste in the mouth
  • dry mouth
  • increased or decreased appetite
  • toothache
  • trouble falling asleep or staying asleep
  • unusual dreams or nightmares
  • headache
  • lack of energy
  • back, joint, or muscle pain
  • abnormal menstrual cycles

How long can you take Varenicline?

Most people take Varenicline for 12 weeks.

Is Varenicline safe during pregnany?

Given the uncertainty about the safety of Varenicline and bupropion during pregnancy, these therapies are not recommended in pregnant women.

Is Varenicline safe during breastfeeding?

Varenicline might interfere with normal infant lung development and recommends against its use in nursing mothers.Because no information is available on the use of brans during breastfeeding, an alternate drug is preferred, especially while nursing a newborn or preterm infant.

Can you drink alcohol while taking Varenicline?

Varenicline can alter people's reaction when drinking alcohol, potentially causing a lowered tolerance, blackouts, and aggressive behavior.

Can I smoke on Varenicline?

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.

Can I take Varenicline forever?

You should take Varenicline for the full 12 or 24 weeks (3 or 6 months), depending on the quit approach you and your healthcare provider decide is right for you.

Does Varenicline make I tired?

Varenicline may make you feel sleepy, dizzy, or have trouble concentrating, making it hard to drive or perform other activities safely.

Does Varenicline cause weight gain?

Varenicline can cause notoriously weird, vivid dreams, and is believed by many to have darker psychiatric effects.

What are the long term effects of taking Varenicline?

depression, mania, psychosis, hallucinations, paranoia, delusions, homicidal ideation, aggression, hostility, anxiety, and panic, as well as suicidal ideation, suicide attempt, and completed suicide in patients attempting to quit smoking while taking Varenicline.

Can Varenicline raise your blood pressure?

Nicotine patches and the stop-smoking pills can potentially increase blood pressure.

Is Varenicline addictive?

May produce mild physical dependence which is not associated with addiction.

How many people died from taking Varenicline?

Anti-smoking drug Varenicline linked to more than 500 suicides.

Is Varenicline bad for my heart?

Varenicline has been linked to an increased risk for heart attacks, strokes, and other cardiovascular events.

What is the best time of day to take Varenicline?

Varenicline should always be taken after eating, with a full glass of water. During the first week of taking Varenicline  your dose will gradually increase. 

How long should Varenicline be taken?

You should take Varenicline for the full 12 or 24 weeks (3 or 6 months), depending on the quit approach you and your healthcare provider decide is right for you.

What is the success rate of Varenicline?

Varenicline users were 60% more successful at quitting smoking at 1 year.

Can I drive after taking Varenicline?

Do not drive, cycle or operate machinery until you feel safe again. If you feel dizzy, sit or lie down until you feel better.

How long does it take for Varenicline to build up in your system?

During the first week of taking Varenicline, you will slowly increase the dose over 7 days to give it time to build up in your body.

*** Taking medicines without doctor's advice can cause long-term problems.