What is the recommended micafungin dosing regimen for confirmed Candida albicans infection in adults and children, including dose adjustments for renal or hepatic impairment?

Micafungin Dosing for Confirmed Candida albicans Infection

For confirmed Candida albicans infection in adults, administer micafungin 100 mg IV once daily, continuing for at least 2 weeks after documented bloodstream clearance and symptom resolution. 1

Adult Dosing Regimen

Standard Candidemia/Invasive Candidiasis

• Micafungin 100 mg IV once daily is the recommended dose for invasive candidiasis and candidemia 1, 2
• Treatment duration: Continue for at least 14 days after documented clearance of Candida from bloodstream AND complete resolution of symptoms attributable to candidemia 1, 2
• Obtain blood cultures daily or every other day until cultures no longer yield yeast to establish clearance timepoint 1

Esophageal Candidiasis

• Micafungin 150 mg IV once daily for esophageal candidiasis 2, 3
• Treatment duration: 14-21 days until clinical improvement 2
• The 150 mg dose demonstrates superior endoscopic cure rates (89.8%) compared to 50 mg (68.8%) in HIV-positive patients 3

Critically Ill/ICU Patients

• Micafungin 100 mg IV once daily remains the standard dose even in severe sepsis with possible abdominal source 1, 4
• Echinocandins (including micafungin) are strongly preferred as first-line therapy for critically ill patients over fluconazole 1, 4
• Surgical source control is mandatory in addition to antifungal therapy for intra-abdominal candidiasis 4

Pediatric Dosing (≥4 months of age)

• Micafungin 2 mg/kg IV once daily (maximum 100 mg) for invasive candidiasis in children ≥4 months 1, 2
• For neonates with disseminated candidiasis, echinocandins should be used with caution and generally limited to salvage therapy; amphotericin B deoxycholate 1 mg/kg daily is preferred 1
• Higher doses (up to 10 mg/kg) may be considered for suspected CNS involvement due to dose-dependent CNS penetration 1

Dose Adjustments for Organ Impairment

Renal Impairment

• No dose adjustment required for any degree of renal impairment, including severe renal dysfunction (CrCl <30 mL/min) 2, 5
• Micafungin is highly protein-bound and not dialyzable; no supplementary dosing needed after hemodialysis 5

Hepatic Impairment

• No dose adjustment required for moderate hepatic impairment (Child-Pugh 7-9) 2, 5
• No dose adjustment required for severe hepatic impairment (Child-Pugh 10-12) 2, 5, 6
• Despite 30% lower AUC in severe hepatic dysfunction, exposures remain comparable to those in patients with systemic Candida infection and are clinically adequate 5, 6

Species-Specific Considerations for C. albicans

• C. albicans demonstrates excellent susceptibility to micafungin with MIC typically 0.03 mg/L 1
• Clinical outcomes with micafungin for C. albicans are superior: anidulafungin (a similar echinocandin) achieved 81% global response vs. 62% with fluconazole specifically for C. albicans infections 1
• Microbiological eradication rates are higher with echinocandins than fluconazole for C. albicans 1

Step-Down Therapy

• Transition to fluconazole 400 mg (6 mg/kg) daily is appropriate once the patient is clinically stable, blood cultures have cleared, and C. albicans susceptibility to fluconazole is confirmed 1, 7
• This allows for potential completion of therapy with oral fluconazole 7
• Do not transition to azoles before confirming species identification and susceptibility 4, 7

Critical Monitoring Requirements

• Dilated funduscopic examination within the first week after diagnosis to rule out endophthalmitis (perform by ophthalmologist if possible) 1, 4
• For neutropenic patients, delay ophthalmologic examination until neutrophil recovery 1
• Blood culture monitoring every 1-2 days until clearance documented 1
• For persistent candidemia, obtain imaging of genitourinary tract, liver, and spleen 1, 4

Common Pitfalls and Caveats

Timing of Initiation

• Initiate therapy within 24 hours of positive blood culture; delays are associated with significantly increased mortality 4, 7
• Mortality approaches 100% in septic shock patients without adequate antifungal therapy and source control within 24 hours 4

Duration Errors

• Do not prematurely discontinue therapy before completing at least 2 weeks after blood culture clearance; premature discontinuation leads to relapse 4, 7
• The 2-week clock starts from the first negative blood culture, not from initiation of therapy 1, 2

Central Venous Catheter Management

• Remove CVCs as early as safely possible when the catheter is the presumed source 1
• CVC removal is associated with improved outcomes and is a strong recommendation 1

Drug Interactions

• Micafungin has minimal drug-drug interactions as it is not significantly metabolized by CYP450 enzymes 8
• No clinically significant interactions require dose adjustment 1, 8

Neutropenic Patients

• Echinocandins are strongly preferred for neutropenic patients with candidemia 1, 7
• Sources other than CVCs (e.g., gastrointestinal tract) predominate in neutropenic hosts 1
• Most neutropenic patients with malignancy are successfully treated with micafungin 100 mg daily 9

Evidence Quality

The 2016 IDSA guidelines provide strong recommendations with moderate-to-high quality evidence for micafungin 100 mg daily as initial therapy for candidemia 1. The recommendation is based on multiple randomized controlled trials demonstrating non-inferiority to liposomal amphotericin B and comparable efficacy to other echinocandins 1, 9. For C. albicans specifically, echinocandins demonstrate superior outcomes compared to fluconazole in critically ill patients 1.