Varenicline Tartrate

(BANM, USAN, rINNM)
Synonyms: CP-526555-18; Tartrato de vareniclina; Varénicline, Tartrate de; Vareniclini Tartras.
Cyrillic synonym: Варениклина Тартрат.

💊 Chemical information

Chemical formula: C13H13N3,C4H6O6 = 361.3.
CAS — 375815-87-5.
ATC — N07BA03.
ATC Vet — QN07BA03.

💊 Adverse Effects and Precautions

The most common adverse effect of varenicline is nausea; other adverse effects also commonly reported are headache, dizziness, somnolence, fatigue, sleep disturbances, increased appetite, and gastrointestinal disturbances including vomiting, constipation, and flatulence. There have been reports of neuropsychiatric symptoms as well as exacerbation of pre-existing psychiatric illness in patients who have taken varenicline. Patients should be monitored for such symptoms, including suicidal ideation or behaviour, agitation, depression, or other changes in behaviour. Dizziness and somnolence may affect the performance of skilled tasks such as driving.

💊 Pharmacokinetics

Varenicline is well absorbed from the gastrointestinal tract, reaching peak plasma concentrations within 3 to 4 hours; bioavailability is high. Steady state concentrations are reached within 4 days of multiple oral dosing. Metabolism is minimal and about 92% of a dose is excreted unchanged in the urine; the elimination half-life is about 24 hours.
1. Faessel HM, et al. Single-dose pharmacokinetics of varenicline, a selective nicotinic receptor partial agonist, in healthy smokers and nonsmokers. J Clin Pharmacol 2006; 46: 991–8
2. Burstein AH, et al. Pharmacokinetics, safety, and tolerability after single and multiple oral doses of varenicline in elderly smokers. J Clin Pharmacol 2006; 46: 1234–40
3. Burstein AH, et al. Pharmacokinetics, safety, and tolerability after single and multiple oral doses of varenicline in elderly smokers. J Clin Pharmacol 2006; 46: 1234–40
4. Faessel HM, et al. Multiple-dose pharmacokinetics of the selective nicotinic receptor partial agonist, varenicline, in healthy smokers. J Clin Pharmacol 2006; 46: 1439–48.

💊 Uses and Administration

Varenicline is a selective nicotinic receptor partial agonist that is used as an aid for smoking cessation. Varenicline is given orally as the tartrate with doses expressed in terms of the equivalent amount of varenicline; 1.71 mg of varenicline tartrate is equivalent to about 1 mg of varenicline. An initial dose equivalent to 500 micrograms varenicline is given once daily for the first 3 days, increasing to 500 micrograms twice daily for the next 4 days. The dose from the eighth day for the remainder of the course is 1 mg twice daily. The dose may be reduced to 500 micrograms twice daily if adverse effects are intolerable. Patients are advised to set a date to stop smoking and start varenicline 1 to 2 weeks before. Treatment is normally given for 12 weeks; in patients who successfully stop smoking, a further 12 weeks of treatment has been recommended to reduce the risk of relapse. For doses in renal impairment, see below.
1. Zierler-Brown SL, Kyle JA. Oral varenicline for smoking cessation. Ann Pharmacother 2007; 41: 95–9
2. Potts LA, Garwood CL. Varenicline: the newest agent for smoking cessation. Am J Health-Syst Pharm 2007; 64: 1381–4
3. Hays JT, et al. Efficacy and safety of varenicline for smoking cessation. Am J Med 2008; 121 (suppl 1): S32–S42
4. Anonymous. Varenicline for smoking cessation. Drug Ther Bull 2008; 46: 33–6.

Administration in renal impairment.

In patients with severe renal impairment (creatinine clearance less than 30 mL/minute) licensed product information recommends a starting dose of 500 micrograms daily increased if necessary after 3 days to a maximum dose of 500 micrograms twice daily (in the USA) or 1 mg once daily (in the UK). In patients with endstage renal disease undergoing haemodialysis, a maximum dose of 500 micrograms once daily may be given provided that this is well tolerated. No dosage adjustment is considered to be needed in patients with lesser degrees of impairment.

Smoking cessation.

Varenicline is an α4β2 nicotinic acetylcholine receptor partial agonist that is used as an aid for smoking cessation. Results from 2 randomised controlled studies1,2 show greater efficacy than placebo as well as favourable results compared with bupropion, a standard treatment for smoking cessation. However, these studies also showed that nausea was reported in almost 30% of participants in the varenicline group; abnormal dreams were also a problem. A further 12 weeks of treatment with varenicline improved abstinence at 24 weeks in patients who stopped smoking in the first 12 weeks of treatment; after stopping all treatment, the reduced relapse rate was maintained in this group up to 28 weeks later (i.e. 1 year from the start of treatment).3
1. Gonzales D, et al. Varenicline, an α4β2 nicotinic acetylcholine receptor partial agonist, vs sustained-release bupropion and placebo for smoking cessation: a randomized controlled trial. JAMA 2006; 296: 47–55
2. Jorenby DE, et al. Efficacy of varenicline, an α4β2 nicotinic acetylcholine receptor partial agonist, vs placebo or sustained-release bupropion for smoking cessation: a randomized controlled trial. JAMA 2006; 296: 56–63. Correction. ibid.; 1355
3. Tonstad S, et al. Effect of maintenance therapy with varenicline on smoking cessation: a randomized controlled trial. JAMA 2006; 296: 64–71.

💊 Preparations

Proprietary Preparations

Austral.: Champix; Braz.: Champix; Cz.: Champix; Fr.: Champix; Gr.: Champix; Hung.: Champix; NZ: Champix; Port.: Champix; UK: Champix; USA: Chantix.
Published May 08, 2019.