From the Guidelines
The recommended treatment for histoplasmosis is liposomal amphotericin B (3 mg/kg daily) for 1-2 weeks, followed by itraconazole (200 mg twice daily) for at least 1 year, as this regimen has been shown to provide a survival benefit in patients with advanced HIV and disseminated histoplasmosis 1.
Treatment Approach
The treatment approach for histoplasmosis depends on the severity and type of infection. For mild to moderate acute pulmonary histoplasmosis, treatment may not be necessary as it often resolves on its own. However, for more severe or disseminated cases, antifungal therapy is crucial to prevent complications.
- The first-line treatment for severe cases is liposomal amphotericin B, which is administered intravenously for 1-2 weeks.
- This is followed by itraconazole, typically 200 mg twice daily, for at least 1 year.
- For central nervous system involvement, higher doses of liposomal amphotericin B may be used.
- Patients with compromised immune systems may require longer treatment durations and sometimes lifelong suppressive therapy with itraconazole.
Monitoring Treatment Effectiveness
Treatment effectiveness should be monitored through clinical improvement and follow-up imaging.
- Blood levels of itraconazole should be obtained to ensure adequate drug exposure 1.
- Antigen levels should be measured during therapy and for 12 months after therapy is ended to monitor for relapse 1.
Special Considerations
Histoplasmosis is caused by inhaling spores of the fungus Histoplasma capsulatum, which primarily affects the lungs but can spread throughout the body, particularly in immunocompromised individuals.
- In patients with AIDS, the timing of antiretroviral therapy poses an interesting dilemma, but antiretroviral therapy should not be withheld on the basis of concern about the possible development of immune reconstitution inflammatory syndrome 1.
- Suppressive therapy should be resumed if patients become nonadherent with antiretroviral therapy, if antiretroviral therapy is failing, or if the CD4 T cell count decreases to <150 cells/mm3 1.
From the FDA Drug Label
Amphotericin B for Injection USP is specifically intended to treat potentially life-threatening fungal infections: ... histoplasmosis... The recommended treatment for histoplasmosis is amphotericin B (IV), as it is specifically intended to treat this potentially life-threatening fungal infection 2.
- Key points:
- Amphotericin B for Injection USP should be administered primarily to patients with progressive, potentially life-threatening fungal infections.
- Histoplasmosis is one of the fungal infections that amphotericin B is intended to treat.
From the Research
Treatment Options for Histoplasmosis
The treatment for histoplasmosis depends on the severity of the disease and the patient's immune status.
- For severe histoplasmosis, amphotericin B is the treatment of choice 3.
- For mild to moderate histoplasmosis, itraconazole is a suitable option 4, 3.
- Fluconazole can be used as an alternative for patients who cannot take itraconazole due to drug interactions, malabsorption, or side effects 5, 6.
- Posaconazole may be considered as a salvage treatment option for severe forms of histoplasmosis 7.
Treatment Duration and Dosage
- Itraconazole therapy typically consists of a loading dose of 300 mg twice a day for 3 days, followed by 200 mg twice a day for 12 weeks 4.
- Fluconazole dosage ranges from 100 to 400 mg per day, with a typical dosage of 800 mg daily for induction therapy and 400 mg daily for maintenance therapy 5, 6.
- Posaconazole is administered as an oral suspension at a dose of 800 mg per day in divided doses, with treatment duration ranging from 6 weeks to 34 weeks 7.
Patient Response and Outcomes
- Patients with mild to moderately severe clinical manifestations of disseminated histoplasmosis have shown significant response to itraconazole therapy, with an overall response rate of 85% 4.
- Fluconazole therapy has been shown to be effective in preventing relapse of histoplasmosis in patients with AIDS, with a relapse-free rate of 53% at 1 year 6.
- Posaconazole salvage treatment has been associated with successful clinical outcomes in patients with severe forms of histoplasmosis, although the number of patients evaluated is small 7.