MICAFUNGIN IN SODIUM CHLORIDE 0.9%
Clinical safety rating: safe
No significant drug interactions Can cause hypernatremia and fluid overload.
Micafungin is an echinocandin antifungal that inhibits the synthesis of 1,3-beta-D-glucan, an essential component of the fungal cell wall, leading to osmotic instability and cell death.
| Metabolism | Micafungin is metabolized by arylsulfatase and catechol-O-methyltransferase (COMT) to the M1 metabolite, and further metabolized by CYP3A4 to M2; however, CYP3A4 plays a minor role. The drug is not a significant inhibitor or inducer of CYP enzymes. |
| Excretion | Primarily biliary/fecal (≈71% of administered dose recovered in feces as parent drug and metabolites); renal excretion accounts for ≈15% (urine: <1% as unchanged drug). |
| Half-life | Terminal elimination half-life is approximately 13-20 hours in adults; supports once-daily dosing. Half-life is prolonged in moderate-to-severe hepatic impairment (Child-Pugh B/C) but no dosage adjustment is required. |
| Protein binding | Highly protein-bound (≥99.8%), primarily to albumin; slight binding to α1-acid glycoprotein. |
| Volume of Distribution | Volume of distribution at steady state (Vss) is approximately 0.2-0.3 L/kg in adults; indicates limited tissue distribution, primarily confined to plasma and interstitial fluid. |
| Bioavailability | Only available as intravenous infusion; oral bioavailability is negligible (<0.1%) due to poor gastrointestinal absorption. |
| Onset of Action | Intravenous administration: onset of antifungal activity is rapid; steady-state concentrations achieved after 4-5 daily doses (loading dose not required per US labeling). |
| Duration of Action | Duration of antifungal effect persists for at least 24 hours with once-daily dosing; clinical response typically assessed after 48-72 hours of therapy. |
100 mg intravenously once daily for invasive candidiasis; 150 mg intravenously once daily for esophageal candidiasis.
| Dosage form | SOLUTION |
| Renal impairment | No dosage adjustment required for any degree of renal impairment. |
| Liver impairment | In moderate hepatic impairment (Child-Pugh B), reduce dose to 100 mg once daily; no data for severe impairment (Child-Pugh C). No adjustment for mild impairment. |
| Pediatric use | For invasive candidiasis: 2 mg/kg (max 100 mg) intravenously once daily for patients ≥40 kg; 2 mg/kg once daily for patients <40 kg. For esophageal candidiasis: 3 mg/kg (max 150 mg) once daily. |
| Geriatric use | No specific dose adjustment; use standard adult dosing based on renal and hepatic function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
No significant drug interactions Can cause hypernatremia and fluid overload.
| FDA category | Animal |
| Breastfeeding | Unknown if micafungin is excreted in human milk. Due to high molecular weight (ca. 1292 Da) and high protein binding (>99%), excretion is likely minimal. M/P ratio not determined. Caution advised; consider alternative therapy or temporarily discontinue breastfeeding during infusion. |
| Teratogenic Risk | Micafungin is classified as FDA Pregnancy Category C. In animal studies, embryotoxicity and skeletal abnormalities were observed at doses 0.04 times the human dose. No adequate human studies exist. First trimester: Theoretical risk based on animal data; use only if benefit justifies risk. Second/third trimester: Limited data; may be used if clearly needed due to lack of alternative therapy. |
■ FDA Black Box Warning
There is no FDA black box warning for micafungin.
| Common Effects | fluid replacement |
| Serious Effects |
["Hypersensitivity to micafungin or any component of the formulation"]
| Precautions | ["Hypersensitivity reactions, including anaphylaxis and anaphylactoid reactions","Hepatic effects: elevations in liver enzymes, bilirubin, and rare cases of hepatic necrosis or hepatitis","Renal effects: elevations in serum creatinine and BUN","Hematologic effects: hemolytic anemia, leukopenia, thrombocytopenia","Injection site reactions: phlebitis, thrombophlebitis","Photosensitivity and risk of skin malignancies in patients with prolonged exposure"] |
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| Fetal Monitoring | Monitor liver function tests (ALP, AST, ALT, bilirubin) due to potential hepatotoxicity; renal function tests (serum creatinine, BUN) as micafungin is cleared in part renally; complete blood count (CBC) for possible hemolytic anemia; and signs of infusion-related reactions (rash, pruritus, hypotension). Fetal monitoring: standard fetal growth and well-being assessments if used during pregnancy. |
| Fertility Effects | No human data on fertility impact. Animal studies: no impairment of male or female fertility at systemic exposures similar to human therapeutic exposures. |