{Smoking Cessation}

VARENICLINE

Adult Dosing

• Smoking cessation
  • Set date to stop smoking, initiate 8-35 days prior
  • Initial 0.5 mg PO qD x 3 days, THEN
  • 0.5 mg PO BID x 4 days, THEN
  • 1 mg PO BID x 11 wks
  • If successful in quitting after 12 wks, continue another 12 wk at 1 mg BID
• If pt unable to abruptly quit smoking during Tx, may consider:
  • Reduce smoking by 50% from baseline within first 4 wks of Tx, THEN
  • By additional 50% in next 4 wks, THEN
  • Continue reducing with goal of reaching complete abstinence by 12 wks
• Administration
  • Take PC dose with full glass of water

Pediatric Dosing

• <17 yo: Safety & efficacy not established

Renal and Hepatic Dosing

• Renal
  • Mild to moderate impairment: no dose adjustment necessary
  • Severe impairment: initial 0.5 mg qD, titrate to NMT 0.5 mg BID
  • ESRD undergoing HD: NMT 0.5 mg qD
• Hepatic
  • No dose adjustment necessary

Contraindications and Cautions

• Contraindications
  • Hypersensitivity
• Cautions
  • Possibility of serious neuropsychiatric d/o, incl suicidal thoughts, abnormal dreams & agitation
    • Weigh risk/benefit of Tx with Hx
  • Seizures reported in postmarketing
    • Weigh risk/benefit of Tx with factors that can lower seizure threshold or Hx
  • Possible interaction with EtOH
    • Increased intoxication reported in postmarketing
  • May affect alertness & ability to perform hazardous tasks
  • High incidence of nausea; generally mild and transient
  • Cardiovascular events may occur; monitor for S/S of MI and stroke
  • Serious skin reactions including Stevens-Johnson Syndrome and erythema multiforme are reported

Indications & Uses

• Smoking cessation (Go to Evidence-Based Inquiry)

Mechanism of Action

• Agonist at nicotinic receptors

Adverse Drug Reactions

• >10%
  • abnormal dreams
  • headache
  • insomnia
  • nausea (up to 40% w/ 1 mg BID)
• 1-10%
  • appetite changes, chest pain, constipation, dry mouth, dysgeusia, flatulence, GERD, fatigue/lethargy, pruritus, rash, somnolence, upper resp tract d/o, vomiting
• Frequency not defined (selective)
  • abnormal LFTs, accidental injury, anemia, angina, angioedema, anxiety, arrhythmia, arthralgia, depression, diarrhea, dizziness, epistaxis, erythema multiforme, HTN, MI, neuropsychiatric symptoms, polyuria, respiratory d/o, Stevens-Johnson Syndrome

Pregnancy and Lactation

• Pregnancy
  • Risk Summary: available data have not suggested increased risk of adverse fetal outcomes
    • Shown to be superior to nicotine patches for cessation during pregnancy
  • Human Data: available data cannot establish or exclude varenicline-assoc risk during pregnancy
  • Animal Data: no major malformations but decreased fetal weights observed at ~50x MRHD
• Lactation
  • Risk Summary: may be present in human milk based on animal data
    • May interfere with normal infant lung development
  • Effect on production: unknown
  • Minimizing exposure: manufacturer recommends weigh risk/benefit of breastfeeding with Tx
    • Alternate agent may be preferred, especially while nursing newborn or preterm infant
• Reproductive Risk
  • Contraception: no specific recommendations
  • Fertility: no evidence of impaired fertility in animal studies at >35x MRHD

Kinetics/Dynamics

• Half-Life: 24 hr
• Absorption: complete
• Bioavailability: high
• Peak Plasma Time: 3-4 hr
• Protein Bound: <20%
• Metabolism: minimal
• Excretion: urine 92%

Overdose Management

• Standard supportive measures
• Has been shown to be dialyzed in pts with ESRD

Interactions

• Go to Drug Interactions [DI]

Trade Names

• Dosing Strengths: (tabs) 0.5 mg, 1 mg

• United States: Chantix
• Canada: Champix

Other Information

• Class: Smoking Cessation
• Requires prescription
• ATC Code: N07BA03
• US Cost Info: Generic ($$$$) | Brand ($$$$)
• Medicare Part D: Coverage

Evidence-Based Inquiry

1. What are the most effective ways you can help patients stop smoking?

References

1. ASHP Drug Compendium (Varenicline tartrate; Autonomic Drugs, Miscellaneous)
2. FDA Monograph varenicline (Chantix) https://www.accessdata.fda.gov/drugsatfda_docs/label/2019/021928s048lbl.pdf (Accessed August 2024)
3. Choi SKY, Tran DT, Kemp-Casey A, et al. The Comparative Effectiveness of Varenicline and Nicotine Patches for Smoking Abstinence During Pregnancy: Evidence From a Population-based Cohort Study. Nicotine Tob Res. 2021 Aug 29;23(10):1664-1672.
4. Maritz GS. Are nicotine replacement therapy, varenicline or bupropion options for pregnant mothers to quit smoking? Effects on the respiratory system of the offspring. Ther Adv Respir Dis 2009;3:193-210.
5. Singh D, Saadabadi A. Varenicline. [Updated 2022 Dec 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534846/

Contributor(s)

1. Reiner, Stefan, PharmD

Updated/Reviewed: August, 2024