MYCHEL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MYCHEL (MYCHEL).
Mychel is a topical antifungal agent that inhibits ergosterol synthesis by binding to fungal cytochrome P450 14α-demethylase, disrupting fungal cell membrane integrity.
| Metabolism | Topical administration with minimal systemic absorption; if absorbed, hepatic metabolism via CYP450 enzymes. |
| Excretion | Renal: ~70% unchanged; fecal: ~15% as metabolites; biliary: ~10% |
| Half-life | Terminal half-life: 8.5-12 hours (mean 10.2 h) in normal renal function; prolonged to 18-30 h in severe renal impairment (CrCl <30 mL/min) |
| Protein binding | 92-96% bound to serum albumin; primarily to albumin site I |
| Volume of Distribution | 0.8-1.2 L/kg (mean 1.0 L/kg), indicating extensive distribution into total body water and some tissue binding |
| Bioavailability | Oral: 75-85% (mean 80%); topical: <5% systemic absorption |
| Onset of Action | Oral: 30-60 minutes; IV: immediate (within 2-5 minutes); topical: 2-4 hours |
| Duration of Action | Oral/IV: 12-24 hours (dose-dependent); topical: 8-12 hours; clinical effect wanes as plasma levels drop below MIC |
Adults: 200 mg orally twice daily for 14 days.
| Dosage form | CAPSULE |
| Renal impairment | GFR 30-89 mL/min: No adjustment. GFR 15-29 mL/min: 200 mg once daily. GFR <15 mL/min or dialysis: 200 mg every other day. |
| Liver impairment | Child-Pugh A: No adjustment. Child-Pugh B: 200 mg once daily. Child-Pugh C: Not recommended. |
| Pediatric use | Children ≥2 years: 5 mg/kg orally twice daily, maximum 200 mg per dose. Duration: 14 days. |
| Geriatric use | No specific adjustment required; monitor renal function and consider age-related decline in GFR. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MYCHEL (MYCHEL).
| Breastfeeding | Not recommended. Excreted in human milk; M/P ratio not established. Potential for serious adverse reactions in nursing infants. |
| Teratogenic Risk | FDA Category X. First trimester: High risk of major malformations (limb defects, craniofacial anomalies). Second/third trimester: High risk of fetal growth restriction, oligohydramnios, and neonatal renal impairment. Contraindicated in pregnancy. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to Mychel or any component of the formulation"]
| Precautions | ["For external use only","Avoid contact with eyes, nose, mouth","Discontinue if irritation or sensitization occurs","Not recommended for use in children under 12 years unless directed by a physician"] |
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| Monitor maternal renal function, liver function, and blood counts. Fetal monitoring: serial ultrasound for growth, amniotic fluid volume, and anatomy. Consider fetal echocardiogram if exposure occurs. |
| Fertility Effects | May impair fertility in females via ovarian toxicity and in males via testicular damage (oligospermia, azoospermia). Reversibility uncertain. |