Mrs. Peterson has been diagnosed with oropharyngeal and esophageal candidiasis. The physician has determined that an oral suspension is the best route of administration and has ordered fluconazole 40 mg/ml, disp 25 ml. She instructed Mrs. Peterson to take 200 mg on the first day, then 100 mg once daily until the medicine is gone. What is the days' supply?

Calculate the total milligrams of fluconazole in the prescription. Total milligrams = Concentration (mg/mL) × Total volume (mL) = 40 mg/mL × 25 mL = 1000 mg. Fluconazole used on the first day = 200 mg. Calculate the remaining milligrams of fluconazole after the first day. Remaining milligrams = Total milligrams - First-day dose = 1000 mg - 200 mg = 800 mg. Calculate the number of days the remaining medication will last. Daily dose after the first day = 100 mg. Remaining days = Remaining milligrams / Daily dose = 800 mg / 100 mg/day = 8 days. Calculate the total days' supply. Total days' supply = Day 1 + Remaining days = 1 day + 8 days = 9 days.