Side Effects of Micafungin

Micafungin is generally well tolerated with minimal adverse effects, making it one of the safest antifungal agents available. 1

Most Common Side Effects

The most frequently reported adverse effects across all patient populations include:

Gastrointestinal effects: Diarrhea (11-77%), nausea (8-71%), vomiting (7-66%), and abdominal pain (16-26%) are the most common side effects 2
Hepatic effects: Increased liver aminotransferase enzyme levels (3-4%), abnormal liver function tests (4%), and elevated alkaline phosphatase (3%) occur but are generally mild 1, 2
Headache: Reported in 9-44% of patients depending on the underlying condition 1, 2
Fever (pyrexia): Occurs in 13-22% of patients, particularly in transplant recipients 2
Infusion-related reactions: Phlebitis (19%) and injection site reactions can occur but are typically manageable 2

In children, the adverse effect profile is similar but with some differences in frequency:

Vomiting (31%), diarrhea (22%), pyrexia (22%), nausea (19%), abdominal pain (16%), and thrombocytopenia (15%) are most common 2
Pediatric patients generally tolerate micafungin well, with only 4-7% requiring discontinuation due to adverse effects 2

While uncommon, clinicians must monitor for potentially serious complications:

Hypersensitivity reactions: Anaphylaxis and anaphylactoid reactions including shock can occur, though histamine-like symptoms are rare and may be related to rapid infusion rates 1, 2
Hepatotoxicity: Hepatic impairment, hepatitis, or worsening hepatic failure can develop, though micafungin undergoes minimal hepatic metabolism 3, 2
Hematologic effects: Acute intravascular hemolysis, hemolytic anemia, hemoglobinuria, thrombocytopenia, and neutropenia have been reported 2
Renal effects: Elevations in BUN and creatinine, renal impairment, or acute renal failure may occur 2

Micafungin is generally well-tolerated with minimal impact on liver function and undergoes minimal hepatic metabolism via the catechol-O-methyltransferase pathway 1, 3
No dosage adjustment is needed in hepatic impairment, unlike caspofungin which requires dose reduction 3
The European Medicines Agency has issued a warning regarding potential risk with prolonged micafungin use due to observations in animal studies, though clinical significance remains unclear 3

Micafungin has minimal drug-drug interactions as it is not a major substrate for cytochrome P450 enzymes 1, 3
This represents a significant advantage over azole antifungals which have extensive CYP450-mediated interactions 1

Micafungin is better tolerated than amphotericin B, with fewer treatment discontinuations (4% vs 16% in pediatric studies) 2
In comparative trials with fluconazole, micafungin showed similar overall adverse event rates but with different specific side effect profiles 2
Echinocandins as a class, including micafungin, are generally well tolerated with few side effects 1, 3

Monitor liver function tests before and during therapy, though hepatotoxicity is uncommon 3
Watch for signs of hypersensitivity, particularly during initial infusions 2
Monitor renal function, electrolytes (particularly potassium), and complete blood counts 2
Infuse slowly over approximately 1 hour to minimize infusion-related reactions 1

Only 4-7% of patients discontinue micafungin due to adverse reactions, demonstrating excellent overall tolerability 2, 4
This compares favorably to other antifungal agents, with micafungin showing numerically fewer discontinuations than fluconazole (4.2% vs 7.2%) 4

Pregnant women and females of reproductive potential should be advised of potential risks to the fetus 2
Women should inform their healthcare provider of known or suspected pregnancy 2