ELASE-CHLOROMYCETIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ELASE-CHLOROMYCETIN (ELASE-CHLOROMYCETIN).
Elase-Chloromycetin is a combination product containing fibrinolysin and desoxyribonuclease (Elase) for enzymatic debridement, and chloramphenicol (Chloromycetin), a bacteriostatic antibiotic that inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit.
| Metabolism | Chloramphenicol is primarily metabolized by hepatic glucuronidation via UDP-glucuronosyltransferases; minor metabolism via reduction to aryl amine. Fibrinolysin and desoxyribonuclease are locally degraded. |
| Excretion | Chloramphenicol is primarily excreted renally (approximately 90% as inactive metabolites). Fecal excretion accounts for less than 1% of the dose. Biliary elimination is negligible. Elase (fibrinolysin and desoxyribonuclease) is locally degraded and not systemically absorbed, thus its excretion is irrelevant. |
| Half-life | Chloramphenicol has a terminal elimination half-life of 1.5 to 4.0 hours in adults with normal renal and hepatic function. In neonates, half-life can be prolonged to 24-48 hours, necessitating dose adjustment. Elase has no systemic half-life as it acts locally. |
| Protein binding | Chloramphenicol is 50-60% bound to serum albumin. Elase components are not systemically absorbed and do not undergo protein binding. |
| Volume of Distribution | Chloramphenicol has a volume of distribution (Vd) of 0.6-1.0 L/kg, indicating extensive tissue distribution. For Elase, Vd is not applicable as it is administered topically and not absorbed. |
| Bioavailability | Chloramphenicol: Oral bioavailability is 75-90% for the palmitate ester; intravenous administration achieves 100% bioavailability. Topical bioavailability of chloramphenicol from Elase-Chloromycetin is minimal, estimated <5% due to local application. |
| Onset of Action | For topical application, onset of action for Elase-Chloromycetin: rapid debridement and antibacterial effect within 24-48 hours. Chloramphenicol systemic absorption from topical use is minimal; systemic effects not relevant. For systemic chloramphenicol, onset of action is within 30-60 minutes after oral or intravenous administration. |
| Duration of Action | Topical: Duration of effect lasts until the enzyme or antibiotic is removed or degraded. Local healing effects may persist for days with continued application. Systemic chloramphenicol duration of action is 6-8 hours after a single dose, requiring q6h dosing for sustained therapeutic levels. |
Topical application: Apply thin layer to affected area 2-3 times daily.
| Dosage form | OINTMENT |
| Renal impairment | No dose adjustment required for topical use; systemic absorption minimal. |
| Liver impairment | No dose adjustment required for topical use. |
| Pediatric use | Topical use: Apply thin layer to affected area 2-3 times daily; safety in infants not established. |
| Geriatric use | Use same as adult dosing; monitor for skin irritation. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ELASE-CHLOROMYCETIN (ELASE-CHLOROMYCETIN).
| Breastfeeding | Chloramphenicol is excreted into breast milk in concentrations sufficient to cause serious adverse effects in nursing infants (bone marrow suppression, Gray baby syndrome). The milk-to-plasma ratio is approximately 0.5. ELASE components are likely not absorbed orally. Contraindicated during breastfeeding. |
| Teratogenic Risk | Chloramphenicol crosses the placenta and may cause Gray baby syndrome (cardiovascular collapse, cyanosis, death) in neonates if administered near term. In the first trimester, its use is associated with a slight increase in congenital anomalies, though data are limited. The desoxyribonuclease and fibrinolysin components (ELASE) are large proteins not expected to cross placenta significantly. Overall, avoid use during all trimesters unless no safer alternative. |
■ FDA Black Box Warning
Chloramphenicol component: Serious and fatal blood dyscrasias (aplastic anemia, hypoplastic anemia, thrombocytopenia, granulocytopenia) have been reported after both systemic and topical administration.
| Serious Effects |
Hypersensitivity to chloramphenicol or any component; patients with a history of blood dyscrasias; concurrent use with other drugs known to cause bone marrow suppression; pregnant or nursing women (relative).
| Precautions | Monitor for bone marrow suppression; avoid prolonged use; use caution in patients with hepatic impairment; risk of systemic absorption from large areas or prolonged application; potential for hypersensitivity reactions. |
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| Fetal Monitoring | CBC with white cell differential weekly due to dose-dependent bone marrow suppression; observe for signs of Gray baby syndrome in fetus/neonate if used near term; fetal ultrasound for congenital anomalies if first-trimester exposure; maternal liver and kidney function monitoring. |
| Fertility Effects | Chloramphenicol may cause transient dose-dependent suppression of spermatogenesis in males. No data on female fertility. ELASE components are not reported to affect fertility. |