Varenicline

Uses

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.

Dosage

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-termabstinence.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.

Precaution

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.

Interaction

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.

Varenicline Disease Interaction

Major: neuropsychiatric eventsModerate: alcoholism, CV disease, renal impairment, seizures

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

Contraindication

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

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