Is there evidence for using Cytisine for smoking cessation?

Evidence for Cytisine in Smoking Cessation

Cytisine appears to be effective for smoking cessation, but the evidence is currently considered not conclusive according to European guidelines. 1

Efficacy of Cytisine

• Cytisine is a low-cost partial nicotine receptor agonist available in some European countries that increases the chances of quitting smoking 1
• Recent systematic reviews and meta-analyses show that cytisine is more effective than placebo (RR = 2.25,95% CI = 1.13-4.47) and nicotine replacement therapy (RR = 1.39,95% CI = 1.12-1.73) for smoking cessation 2
• Cytisine appears to be comparable to varenicline in effectiveness (RR = 1.02,95% CI = 0.72-1.44), though some studies suggest varenicline might have a slight edge 2, 3
• Longer treatment duration of cytisine (extended regimen) has been associated with higher abstinence rates (RR = 1.29,95% CI = 1.02-1.63) 4

Safety Profile

• Cytisine has a relatively benign safety profile with mostly mild adverse events such as gastrointestinal symptoms, abnormal dreams, nausea, and headaches 4, 2
• The difference in adverse events between cytisine and placebo is not statistically significant (RR = 1.19,95% CI = 0.99-1.41) 4
• Cytisine appears to have fewer adverse events compared to varenicline (RR = 0.67,95% CI = 0.48-0.95) 2

Current Guideline Recommendations

• According to the European Society of Cardiology guidelines (2012), cytisine "seems to increase the chances of quitting, but the evidence at present is not conclusive" 1
• First-line pharmacotherapies for smoking cessation with stronger evidence include:
  • Nicotine replacement therapy (NRT) in various forms (patches, gum, nasal spray, inhaler, sublingual tablets) 1
  • Varenicline (partial nicotine receptor agonist) 1
  • Bupropion (antidepressant) 1

Clinical Implementation Considerations

• Cytisine may be particularly valuable in low-resource settings due to its lower cost compared to other smoking cessation medications 5
• The number needed to treat (NNT) for cytisine is estimated at 11 patients to achieve one successful smoking cessation 5
• Behavioral support should be offered alongside cytisine, as with other pharmacological smoking cessation aids 1
• Cytisine is not yet widely available in many countries, which limits its clinical use 1

Limitations and Future Directions

• More research is needed to establish the optimal dosing regimen for cytisine 4, 3
• Current evidence suggests that cytisine is more effective with more intensive behavioral therapy support 5
• A prospective observational study (CITOSP) is currently investigating the safety and efficacy of cytisine in hospital settings 6
• Future trials should directly compare cytisine with varenicline and other pharmacotherapies to strengthen the evidence base 3

In conclusion, while cytisine shows promise as an effective smoking cessation aid with a favorable safety profile, current European guidelines still consider the evidence not conclusive. For patients seeking smoking cessation support, established first-line therapies like NRT, varenicline, and bupropion remain the recommended options, though cytisine may be a valuable alternative, particularly in settings where cost is a significant consideration.