What is the recommended dosing for Ambisome (amphotericin B liposomal) in the treatment of severe pulmonary histoplasmosis according to the Infectious Diseases Society of America (IDSA) guidelines?

From the Guidelines

For severe pulmonary histoplasmosis, the IDSA guidelines recommend liposomal amphotericin B (AmBisome) at a dose of 3.0–5.0 mg/kg daily intravenously for 1–2 weeks. This recommendation is based on the 2007 update by the Infectious Diseases Society of America 1. The use of AmBisome is preferred due to its reduced nephrotoxicity compared to the deoxycholate formulation of amphotericin B. After the initial AmBisome course, patients should transition to oral itraconazole therapy, with a loading dose of 200 mg three times daily for 3 days, followed by 200 mg twice daily for a total of 12 weeks. Some key points to consider when using AmBisome include:

• Monitoring for common side effects such as infusion reactions, electrolyte abnormalities, and renal function impairment
• Premedication with acetaminophen and diphenhydramine to reduce infusion-related reactions
• Consideration of methylprednisolone at 0.5–1.0 mg/kg daily for patients who develop respiratory complications, including hypoxemia or significant respiratory distress, during the first 1–2 weeks of antifungal therapy 1.

From the Research

Ambisome Dosing for Severe Pulmonary Histoplasmosis

• The IDSA guidelines recommend Amphotericin B as the treatment of choice for severe pulmonary or disseminated histoplasmosis 2.
• Liposomal amphotericin B (Ambisome) can be used as a step-down treatment for pulmonary histoplasmosis, with a dose of 250mg (4mg/kg) intravenously thrice weekly 3.
• There is no specific mention of Ambisome dosing for severe pulmonary histoplasmosis in the provided studies, but Amphotericin B is the preferred treatment during pregnancy 3.
• Posaconazole exhibits promise as a salvage agent for histoplasmosis, but its use is not specifically recommended for severe pulmonary histoplasmosis in the provided studies 4, 2, 5.

Treatment Options

• Amphotericin B is the treatment of choice for severe pulmonary or disseminated histoplasmosis 2.
• Itraconazole is effective for mild to moderately severe infection 2.
• Posaconazole may be a useful salvage treatment option for histoplasmosis involving a variety of infected tissues and organs 4, 5.

IDSA Guidelines

• The IDSA guidelines recommend itraconazole for acute pulmonary, mild-moderate disseminated, and as step-down therapy for severe disseminated histoplasmosis 6.
• There is a need for updated guidelines to reflect the growing need for general guidance, particularly for immunocompromised populations 6.