Antifungals

Understanding Antifungal Agents

Overview of Fungi and Mycosis

• Fungi are cellular organisms characterized by a hard cell wall composed of chitin and polysaccharides. The presence of ergosterol in their cell membranes is significant for antifungal treatment. Any fungal infection is termed mycosis.

Importance of Monitoring Systemic Antifungals

• Systemic fungal infections can be life-threatening, especially with the rise in immunocompromised patients. Resistance to antifungals can occur, making it crucial to obtain a culture before treatment. Close monitoring is necessary due to potential drug interactions affecting liver function.

Azole Antifungals: Efficacy and Toxicity

• Azole antifungals are widely used for treating systemic and topical infections but may be less effective in severe cases despite being less toxic than other options. Their action can be fungicidal or fungistatic depending on the fungus type and drug concentration.

Specific Antifungal Agents: Ketoconazole and Fluconazole

• Ketoconazole has severe hepatic toxicity risks; thus, it should be avoided in patients with liver dysfunction or endocrine issues. In contrast, fluconazole poses fewer endocrine problems but requires caution in patients with liver or renal toxicity.

Terbinafine and Other Considerations

• Terbinafine is contraindicated in liver failure as it may cross the placenta and enter breast milk, posing risks during pregnancy or nursing. Monitoring QT interval prolongation is essential when using certain drugs alongside terbinafine due to potential cardiac effects.

Drug Interactions and Adverse Effects

• Many azoles can cause liver toxicity; hence, they require careful patient monitoring for adverse effects, particularly concerning serum levels of co-administered medications like anticoagulants or hypoglycemics that could lead to increased side effects.

Glucan Synthesis Inhibitors: Anidulafungin and Caspofungin

• Anidulafungin inhibits glucan synthesis critical for fungal cell walls but not human cells, leading to cell death upon inhibition. It’s administered via IV infusion for at least 14 days; caution is advised during pregnancy due to its ability to cross the placenta and enter breast milk.

Amphotericin B: Usage Guidelines

Antifungal Treatments and Their Implications

Overview of Antifungal Treatment Risks

• The potential risks associated with antifungal treatments, particularly regarding liver and kidney function, necessitate close monitoring through daily laboratory tests.

• Adverse effects include bone marrow suppression, gastrointestinal irritation (nausea, vomiting), severe diarrhea, anorexia, and weight loss; these side effects highlight the need for careful patient management.

Drug Interactions and Precautions

• Patients receiving amphotericin B should avoid nephrotoxic drugs such as certain antibiotics and antineoplastics to prevent compounded renal impairment.

• Caution is advised when using immunosuppressants like cyclosporine or corticosteroids alongside antifungals due to increased risk of adverse reactions.

Types of Mycosis and Treatment Approaches

• Dermatophytes are fungi responsible for various skin mycoses (e.g., ringworm), which require specific topical antifungal treatments.

• Care must be taken with open or draining wounds to prevent systemic absorption of topical medications.

Application Techniques for Topical Antifungals

• Topical antifungals alter fungal cell permeability to inhibit replication; they are indicated only for local treatment of mycosis without systemic absorption.

• Effective application involves targeting intertriginous areas (where skin rubs together), recommending cotton socks over nylon, and changing them frequently to enhance therapeutic response.

Patient Education on Usage and Side Effects

• Patients should wear well-fitting clothing during treatment for jock itch or ringworm; condoms are recommended during sexual activity to prevent infection spread.

• Contraindications include known allergies to antifungal agents; patients must be informed about potential local burning from medications like echinocandins or staining from gentian violet.