MICAFUNGIN SODIUM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MICAFUNGIN SODIUM (MICAFUNGIN SODIUM).
Micafungin inhibits 1,3-beta-D-glucan synthase, an enzyme required for synthesis of 1,3-beta-D-glucan, a key component of fungal cell walls.
| Metabolism | Micafungin is metabolized by arylsulfatase and catechol-O-methyltransferase, with minor involvement of CYP3A4. It is not a substrate for P-glycoprotein. |
| Excretion | Primarily hepatic metabolism; 71% recovered in feces (40% as parent drug, 31% as metabolite) and 11% in urine (1% as parent drug). |
| Half-life | Terminal elimination half-life: 11–17 hours (mean ~14 hours) in healthy adults; prolonged in moderate-to-severe hepatic impairment (up to 20–30 hours). |
| Protein binding | 99.8% bound primarily to albumin; binding is independent of concentration. |
| Volume of Distribution | Volume of distribution: 0.23–0.29 L/kg (range 0.2–0.3 L/kg); indicates limited extravascular distribution, primarily in plasma and interstitial fluid. |
| Bioavailability | Only available as intravenous formulation; oral bioavailability is negligible (<5%) and not clinically used. |
| Onset of Action | Intravenous administration: onset of antifungal activity within 1–2 hours following first dose; steady-state achieved by day 4–5. |
| Duration of Action | Duration of antifungal effect persists for approximately 24 hours, supporting once-daily dosing; clinical effect maintained throughout dosing interval. |
100 mg intravenously once daily; for invasive candidiasis, a loading dose of 200 mg intravenously once on day 1 may be considered.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for any degree of renal impairment, including hemodialysis. Not significantly removed by hemodialysis. |
| Liver impairment | No dose adjustment required for mild or moderate hepatic impairment (Child-Pugh A or B). Insufficient data for severe hepatic impairment (Child-Pugh C); use with caution. |
| Pediatric use | Neonates and infants <4 months: 10 mg/kg intravenously once daily. Children ≥4 months and adolescents: 2-4 mg/kg intravenously once daily (maximum 100 mg daily for patients weighing ≤40 kg; 100 mg daily for patients >40 kg). For invasive candidiasis, loading dose of 3-4 mg/kg intravenously once on day 1 (maximum 200 mg for >40 kg). |
| Geriatric use | No specific dose adjustment recommended. Pharmacokinetics similar to younger adults. Monitor for adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MICAFUNGIN SODIUM (MICAFUNGIN SODIUM).
| Breastfeeding | Micafungin is excreted into human milk in low amounts; M/P ratio not determined. Limited data suggest low infant exposure. Consider developmental benefits of breastfeeding vs. risk of infant exposure; caution recommended. |
| Teratogenic Risk | Limited human data; animal studies show no teratogenicity at clinically relevant doses. First trimester risk cannot be fully excluded; second and third trimester use suggests no increased malformation risk. Exposure may be considered if benefit outweighs unknown risk. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypersensitivity to micafungin or any component of the formulation."]
| Precautions | ["Hepatic effects: Elevated liver enzymes and hepatic dysfunction have been reported, including rare cases of hepatic necrosis and hepatitis.","Renal effects: Elevations in BUN and creatinine may occur.","Hypersensitivity reactions: Anaphylaxis and other allergic reactions have been reported.","Risk of hemolytic anemia and hemolysis."] |
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| Fetal Monitoring |
| Monitor maternal liver function tests (ALT, AST, bilirubin) and renal function (serum creatinine) periodically. In neonates, monitor for hepatotoxicity. No specific fetal monitoring required; standard obstetric ultrasound may be considered. |
| Fertility Effects | Animal studies show no impairment of male or female fertility at clinically relevant doses. Human data on fertility effects are lacking. |