Chantix

Aka: Chantix, Varenicline

1. Indications
   1. Tobacco Cessation
   2. Not considered first-line therapy in teens who use Tobacco
   3. Decreases Alcohol consumption (consider for Tobacco Cessation in comorbid Alcohol Abuse)
      1. Decreases intake by 1 drink daily and 20% fewer heavy drinking days
      2. Mitchell (2012) Psychopharmacology 223(3):299-306 [PubMed]
2. Precautions
   1. FDA Pregnancy Category C
   2. Increased cardiovascular events in Tobacco users with history of cardiovascular disease
      1. http://www.fda.gov/Drugs/DrugSafety/ucm259161.htm
   3. May be used in combination with Nicotine Replacement
      1. Previously, combined Nicotine Replacement AND Chantix was contraindicated
      2. Combined Verenicline with Nicotine Replacement is more effective than either alone without increased adverse effects
         1. Koegelenberg (2014) JAMA 312(2):155-61 [PubMed]
   4. Avoid combination with Bupropion
      1. Safety in combination with Bupropion is unknown
      2. However, both agents increase risk of Seizures
   5. FDA black box warning was removed in 2017 (but still be aware of potential risk)
      1. Serious neuropsychiatric symptoms
      2. May cause depressed mood and Suicidality
      3. May cause behavior change including hostility, Agitation (especially with Alcohol)
3. Mechanism
   1. Nicotine binds nicotinic acetylcholine receptor a4b2
      1. Binding stimulates CNS mesolimbic Dopamine system
      2. Reinforces nicotine exposure
   2. Chantix activity
      1. Chantix Blocks nicotine at a4b2 receptors
      2. Chantix selectively binds a4b2 receptors
4. Dosing
   1. Start: 0.5 mg once daily on days 1 to 3
   2. Next: 0.5 mg twice daily on days 4 to 7
   3. Next: 1 mg twice daily
   4. Duration
      1. Set quit date at 1-5 weeks after starting Chantix (consider quitting at 12 weeks)
      2. Continue for 12 weeks
      3. Additional 12 weeks may be used if successful
         1. Higher abstinence rates with delaying quit date to 12 weeks and continuing Chantix for 24 weeks
         2. Ebbert (2015) JAMA 313(7):687-94 +PMID:25688780 [PubMed]
   5. Dosing adjustment: Renal Impairment
      1. Severe renal Impairment: Max dose 0.5 mg PO bid
      2. End-stage renal disease: Max dose 0.5 mg PO daily
5. Adverse Effects
   1. See precautions above
   2. Nausea (30%)
   3. Headache (10%)
   4. Sleep disturbance (Insomnia, or abnormal dreams): 10%
   5. Constipation
   6. Flatulence
   7. Seizure
      1. Typically at 2-3 weeks after starting Chantix
   8. Suicidal Ideation
      1. Reported in 1 per 10,000 patients taking Chantix
      2. Kuehn (2008) JAMA 299(10):1121-2 [PubMed]
6. Drug Interactions
   1. Alcohol
      1. Increases risk of Intoxication, hostility, aggressive, amnesia behavior
7. Cost
   1. Monthly: $440 (in 2020)
8. Efficacy
   1. Cessation for >1 year in 20% (10% with Placebo)
   2. Cessation rates are as good if not better than Zyban
   3. Number Needed to Treat (for longterm cessation): 9
   4. More effective when combined with Nicotine Replacement
      1. Koegelenberg (2014) JAMA 312(2): 155-61 [PubMed]
9. References
   1. (2020) presc lett 27(9):51-2
   2. Larzelere (2012) Am Fam Physician 85(6): 591-8 [PubMed]
   3. Love (2007) Am Fam Physician 76:279-80 [PubMed]
   4. Oncken (2006) Arch Intern Med 166: 1571-7 [PubMed]
   5. Tonstad (2006) JAMA 296: 64-71 [PubMed]