Varenicline (Chantix) Dosing Regimen for Smoking Cessation
The recommended dosage for Chantix (varenicline) is 1 mg twice daily following a 1-week titration period, with treatment typically lasting 12 weeks. 1
Standard Dosing Schedule
Initial Titration Period
- Days 1-3: 0.5 mg once daily
- Days 4-7: 0.5 mg twice daily
Maintenance Dosing
- Day 8 to end of treatment: 1 mg twice daily
Treatment Duration and Timing
- Standard duration: 12 weeks 2, 1
- Begin dosing 1-2 weeks prior to the target quit date 2
- Alternatively, patients can begin varenicline and quit smoking between days 8-35 of treatment 1
- For patients who successfully quit at 12 weeks, an additional 12-week course (total 24 weeks) is recommended to further increase long-term abstinence 1
Special Populations Dosing Adjustments
Renal Impairment
- Mild to moderate impairment: No dosage adjustment needed
- Severe impairment (CrCl <30 mL/min): Start with 0.5 mg once daily, maximum 0.5 mg twice daily
- End-stage renal disease on hemodialysis: Maximum 0.5 mg once daily 1
Elderly and Hepatic Impairment
- No dosage adjustment required for hepatic impairment
- No specific adjustment for elderly, but monitor renal function 1
Gradual Approach Option
For patients unable or unwilling to quit abruptly:
- Begin varenicline dosing
- Reduce smoking by 50% from baseline within first 4 weeks
- Reduce by additional 50% in next 4 weeks
- Aim for complete abstinence by 12 weeks
- Continue treatment for additional 12 weeks (total 24 weeks) 1
Administration Guidelines
- Take after eating
- Take with a full glass of water 1
- Nausea is common but typically diminishes over time 2, 3
Common Side Effects and Precautions
- Most common side effect: Nausea (occurs in 16-42% of patients) 4
- Monitor for neuropsychiatric symptoms (depression, suicidal ideation)
- Contraindicated for patients with brain metastases due to seizure risk 2
- Contraindicated in patients with history of serious hypersensitivity reactions to varenicline 1
Effectiveness Considerations
Varenicline is considered a preferred primary therapy for smoking cessation, along with combination nicotine replacement therapy 2. It has demonstrated superior efficacy compared to bupropion SR and nicotine replacement therapy in clinical trials 3, 4.
For patients who relapse or fail to quit, consider:
- Continuing the initial pharmacotherapy
- Switching to another primary therapy option
- Adjusting the dose if side effects are problematic 2
Behavioral therapy should be provided alongside pharmacotherapy to maximize success rates, with at least 4 sessions during each 12-week course 2.