MICAFUNGIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MICAFUNGIN (MICAFUNGIN).
Inhibits the synthesis of 1,3-β-D-glucan, an essential component of the fungal cell wall, via inhibition of 1,3-β-D-glucan synthase.
| Metabolism | Primarily metabolized by the liver via the CYP450 system, specifically CYP3A4, though to a minor extent; also metabolized by arylsulfatase and catechol-O-methyltransferase. Mainly excreted unchanged in feces and bile, with minimal renal excretion. |
| Excretion | Primarily biliary/fecal (approximately 71% of administered dose recovered in feces as parent drug and metabolites), with renal excretion accounting for about 12% (mostly as metabolites, <1% unchanged). A small amount is excreted in urine. |
| Half-life | Terminal elimination half-life is approximately 10-17 hours in healthy adults. In critically ill patients, it may be prolonged (up to 20-25 hours). Half-life is dose-independent. |
| Protein binding | Highly protein bound (>99%) primarily to albumin. Saturation of binding occurs at high concentrations (>100 mcg/mL), but clinical relevance is minimal. |
| Volume of Distribution | Volume of distribution at steady state is approximately 0.29-0.39 L/kg. This indicates limited tissue distribution, primarily confined to extracellular fluid. Penetration into certain tissues (e.g., brain, eye) is poor. |
| Bioavailability | Micafungin is only administered intravenously; bioavailability by this route is 100%. Oral bioavailability is negligible (<1%) due to poor absorption. |
| Onset of Action | Intravenous: The antifungal effect begins within 30-60 minutes after infusion start, with peak concentrations achieved at the end of infusion. |
| Duration of Action | The antifungal effect persists for approximately 24 hours, supporting once-daily dosing. Clinical response is evident within 2-4 days for most indications (e.g., candidemia). |
100 mg intravenously once daily. For esophageal candidiasis: 150 mg intravenously once daily. Loading dose not required.
| Dosage form | POWDER |
| Renal impairment | No dose adjustment required for renal impairment, including hemodialysis. |
| Liver impairment | No dose adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B). Insufficient data for severe impairment (Child-Pugh C). |
| Pediatric use | For invasive candidiasis: 2 mg/kg intravenously once daily (maximum 100 mg daily). For prophylaxis: 1 mg/kg intravenously once daily (maximum 50 mg daily). |
| Geriatric use | No specific dose adjustment necessary; use standard adult dosing with renal function monitoring due to age-related decline. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MICAFUNGIN (MICAFUNGIN).
| Breastfeeding | It is not known whether micafungin is excreted in human milk. In lactating rats, micafungin was detected in milk. M/P ratio is unknown. Caution should be exercised when administered to a nursing woman; consider developmental and health benefits of breastfeeding along with mother's clinical need. |
| Teratogenic Risk | Micafungin is classified as FDA Pregnancy Category C. In animal studies, embryotoxicity and teratogenicity were observed at doses below human exposure. There are no adequate and well-controlled studies in pregnant women. Use only if potential benefit justifies potential risk to the fetus. First trimester: Unknown risk; avoid unless necessary. Second and third trimesters: Limited data; consider maternal benefit vs fetal risk. |
■ FDA Black Box Warning
No FDA boxed warning.
| Serious Effects |
["Hypersensitivity to micafungin or any excipient","Severe hepatic impairment (Child-Pugh Class C) – relative contraindication"]
| Precautions | ["Hepatic effects: elevated liver enzymes, hepatitis, hepatic impairment; monitor liver function tests","Renal effects: elevated BUN and creatinine; monitor renal function","Hypersensitivity reactions including anaphylaxis and serious skin reactions","Hematologic effects: hemolytic anemia, thrombocytopenia","Interference with other medications: potential drug interactions with immunosuppressants (e.g., sirolimus, nifedipine)"] |
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| Fetal Monitoring | Monitor liver function tests (ALT, AST, alkaline phosphatase, bilirubin) periodically. Monitor renal function (serum creatinine, BUN). Monitor for signs of infusion-related reactions (rash, pruritus, facial swelling, vasodilation). Obtain baseline and periodic complete blood counts. Ensure patency of intravenous line during infusion. |
| Fertility Effects | In animal studies, micafungin had no adverse effects on fertility in male or female rats at doses up to 32 mg/kg/day (approximately 3 times the human AUC at the recommended dose). No human data on fertility effects. |