Which antifungal drug is used to treat systemic fungal infections and can cause nephrotoxicity?

Choice A reason: Montelukast is not tapered or discontinued when symptoms improve, as it is a maintenance therapy for asthma. Stopping it may lead to recurrence of inflammation, as it blocks leukotriene receptors, preventing bronchoconstriction and inflammation, requiring consistent use for sustained control.

Choice B reason: Montelukast, a leukotriene receptor antagonist, requires daily oral administration to maintain its anti-inflammatory effects by blocking leukotriene D4 receptors. Continuous use prevents asthma exacerbations, even during symptom-free periods, ensuring long-term airway stability and reducing the risk of flare-ups.

Choice C reason: Montelukast is not used for acute asthma attacks due to its slow onset (hours). It is a maintenance therapy, not a rescue medication like albuterol, which provides rapid bronchodilation. Patients should carry beta-agonists, not montelukast, for acute symptom relief.

Choice D reason: Montelukast is an oral tablet, not an inhaled medication, so inhalation technique is irrelevant. Its action involves systemic leukotriene receptor blockade, reducing airway inflammation. Proper administration requires consistent daily dosing, not device-specific techniques, making this instruction incorrect for montelukast.

Choice A reason: Itraconazole is a systemic antifungal used for infections like histoplasmosis. It inhibits ergosterol synthesis but is not typically used topically for athlete’s foot due to its oral or intravenous administration. Its systemic use carries risks like hepatotoxicity, making it unsuitable for localized dermatophyte infections.

Choice B reason: Ketoconazole is available as a topical cream but is less commonly used for athlete’s foot compared to terbinafine. It inhibits fungal ergosterol synthesis and is effective for cutaneous infections, but its topical use is more associated with seborrheic dermatitis or candidiasis, not primarily tinea pedis.

Choice C reason: Terbinafine is a topical antifungal commonly used for athlete’s foot (tinea pedis). It inhibits squalene epoxidase, disrupting fungal cell membrane synthesis, leading to fungal death. Its topical application effectively treats dermatophyte infections like Trichophyton, making it a first-line choice for localized fungal infections.

Choice D reason: Amphotericin B is a systemic antifungal used for severe fungal infections. It binds to ergosterol, causing fungal cell lysis, but is not used topically for athlete’s foot due to its toxicity and intravenous administration. It is reserved for life-threatening systemic infections, not cutaneous conditions.