Antifungal prescriptions treat severe, widespread, or persistent fungal infections beyond over-the-counter (OTC) capabilities. They contain stronger active ingredients or broader-spectrum agents. While OTC products handle minor infections, prescriptions are needed for complex cases requiring a more potent or systemic approach.
Types of Fungal Infections Requiring Prescription
Prescription antifungals are often needed for certain fungal infections due to their nature or severity. Stubborn skin infections, like severe athlete’s foot or widespread ringworm unresponsive to nonprescription products, often need stronger treatments. Oral antifungals like terbinafine or itraconazole may be prescribed for persistent athlete’s foot, especially if deep-seated or involving nails.
Fungal nail infections (onychomycosis) require prescription oral or topical medications due to their deep nature. Oral options include terbinafine or itraconazole, which promote healthy nail growth. Chronic, severe, or recurrent vaginal yeast infections also often require prescription treatments, such as oral fluconazole or longer courses of vaginal creams or suppositories like terconazole.
Systemic fungal infections, affecting organs like the lungs, blood, or brain, always require prescription antifungals due to their serious, life-threatening nature. Examples include aspergillosis, candidemia, or fungal meningitis, especially concerning for those with weakened immune systems. Topical treatments are insufficient as the fungus has spread throughout the body.
Categories of Antifungal Medications
Antifungal prescriptions come in various forms, tailored to the infection’s type and location. Topical antifungals apply directly to the affected area, available as creams, ointments, solutions, gels, sprays, or shampoos. Commonly used for superficial skin infections like athlete’s foot or ringworm, examples include clotrimazole, miconazole, and terbinafine creams. Some, like miconazole formulations, are also available as oral gels or vaginal suppositories for localized candidiasis.
Oral antifungals, taken as pills or liquids, work systemically via the bloodstream. They treat widespread or hard-to-reach infections, such as those affecting nails, scalp, or internal organs. Fluconazole is a common oral antifungal for vaginal yeast infections and certain systemic candidal infections. Terbinafine is often prescribed orally for fungal nail infections, while itraconazole and ketoconazole treat a broader range of fungal conditions, including more serious systemic infections.
Intravenous (IV) antifungals are administered directly into a vein, reserved for severe, invasive systemic fungal infections requiring immediate, potent hospital treatment. Examples include Amphotericin B and echinocandins like caspofungin, used for serious conditions such as aspergillosis or invasive candidiasis. They deliver medication directly into the bloodstream for rapid, effective distribution against widespread fungal pathogens.
How Antifungals Work
Antifungals combat infections by targeting structures unique to fungal cells, minimizing harm to human cells. Many, particularly azoles like fluconazole, interfere with ergosterol synthesis, a major component of the fungal cell membrane. Disrupting ergosterol production destabilizes the fungal cell membrane, leading to cell leakage and death.
Another mechanism targets the fungal cell wall, a rigid outer layer absent in human cells. Echinocandins, for instance, inhibit 1,3-beta-glucan synthase, which builds beta-glucans essential for cell wall integrity. This weakens the cell wall, making the fungal cell prone to bursting. Other antifungals, like polyenes such as amphotericin B, bind directly to ergosterol in the fungal cell membrane, creating pores that cause cell leakage and death. Some agents also inhibit fungal growth by disrupting fungal DNA synthesis or cell division.
Important Considerations for Treatment
Completing the full course of antifungal treatment is important, even if symptoms improve earlier. Stopping prematurely can lead to infection return and contribute to antifungal resistance, making future infections harder to treat. Duration varies significantly, from days for some skin infections to months or years for severe nail, blood, or lung infections.
Antifungals can cause side effects, varying by drug, dosage, and fungus type. Common side effects include gastrointestinal issues (nausea, vomiting, abdominal pain, diarrhea) and skin reactions (itching, burning, rash). More serious, though rare, side effects include liver damage, severe allergic reactions, or severe skin reactions like blistering and peeling. Those with pre-existing liver or kidney conditions may be at increased risk.
Antifungals can interact with other medications, potentially altering effectiveness or increasing adverse reactions. For example, azole antifungals like fluconazole and itraconazole can inhibit liver enzymes, affecting the metabolism of drugs such as statins, benzodiazepines, and warfarin. Terbinafine generally has fewer interactions than azoles. Patients should inform their healthcare provider about all medications, supplements, and health conditions to avoid potential interactions.
Antifungal resistance is a significant concern, occurring when fungi no longer respond to effective treatments. It can develop naturally or from prolonged use, skipped doses, premature cessation, or insufficient dosage. Mechanisms include alterations in the drug target, increased activity of efflux pumps that remove the drug, or changes in cellular pathways. Contact a healthcare provider if symptoms do not improve with treatment, worsen, return after completion, or if any concerning side effects occur.