Onecan 200 Tablet contains Fluconazole 200 mg, an antifungal agent belonging to the triazole class. It is primarily indicated for the treatment of various fungal infections caused by susceptible strains of Candida and Cryptococcus species. Fluconazole acts by inhibiting the fungal cytochrome P450 enzyme 14α-demethylase, which is essential for converting lanosterol to ergosterol, a critical component of the fungal cell membrane. This disruption leads to increased membrane permeability and ultimately fungal cell death. Onecan 200 is commonly prescribed for oropharyngeal, esophageal, and systemic candidiasis, as well as cryptococcal meningitis. It may also be used prophylactically in immunocompromised patients to prevent fungal infections. The tablet is administered orally, with dosage and duration tailored according to the severity and type of infection, patient age, and renal function. Fluconazole is generally well tolerated; however, potential adverse effects include headache, nausea, abdominal pain, and, rarely, hepatotoxicity or QT interval prolongation. Caution is advised when co-administered with drugs metabolized by cytochrome P450 enzymes due to possible drug interactions. Onecan 200 Tablet should be used under medical supervision with appropriate monitoring to ensure efficacy and safety.