Diflucan diarrhea. Fluconazole (Diflucan®) By: Dr. 1. . The most common side effects of DIFLUCAN are: hives, itching, swelling, sudden drop in blood pressure, difficulty breathing or swallowing, diarrhea, or abdominal pain. . . Includes patient rankings, comments, side . . Find patient medical information for Diflucan Oral on WebMD including its uses, side . The most common side effects of DIFLUCAN are: · headache · diarrhea · nausea or upset stomach · dizziness · stomach pain · changes... more