Hi, There is currently no known interaction between fluconazole and Plan B (levonorgestrel emergency contraception). Therefore, it is unlikely that fluconazole will affect the effectiveness of Plan B. However, it is important to note that no form of contraception is 100% effective and there is still a chance of pregnancy even after taking Plan B. If you have any concerns, you should speak with your healthcare provider. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Priyanka, General & Family Physician