MYCIFRADIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MYCIFRADIN (MYCIFRADIN).
Aminoglycoside antibiotic that binds to the 30S ribosomal subunit, inhibiting bacterial protein synthesis by causing misreading of mRNA and incorporation of incorrect amino acids into the growing peptide chain.
| Metabolism | Primarily eliminated unchanged in the feces after oral administration due to poor systemic absorption. Any absorbed fraction is minimally metabolized and excreted renally. |
| Excretion | Primarily renal excretion of unchanged drug via glomerular filtration; >90% of absorbed dose excreted unchanged in urine within 24 hours. Minor biliary excretion (<1%) with fecal elimination accounting for <1%. |
| Half-life | Terminal elimination half-life is 9–12 hours in patients with normal renal function; may extend to >20 hours in impaired renal function, necessitating dose adjustment. |
| Protein binding | Approximately 30% bound to plasma proteins (albumin). |
| Volume of Distribution | 0.2–0.4 L/kg, indicating distribution primarily into extracellular fluid. |
| Bioavailability | Intramuscular: nearly 100% (well absorbed); Oral: negligible (<1% due to poor gastrointestinal absorption). |
| Onset of Action | Intramuscular: 1–2 hours; Oral: not available (not absorbed orally due to poor absorption). |
| Duration of Action | Intramuscular: 8–12 hours (clinical effect persists for duration above MIC). |
1-2 g orally every 6 hours for 7-14 days. Or 500 mg intramuscularly every 12 hours.
| Dosage form | TABLET |
| Renal impairment | CrCl 50-90 mL/min: no adjustment; CrCl 10-50 mL/min: 500 mg orally every 12 hours; CrCl <10 mL/min: 500 mg orally every 24 hours. |
| Liver impairment | No dosage adjustment required for Child-Pugh Class A or B; caution in Class C with monitoring. |
| Pediatric use | 25-50 mg/kg/day orally divided every 6 hours; maximum 2 g/day. |
| Geriatric use | Start at lower end of dosing range (500 mg orally every 6 hours); monitor renal function and adjust based on CrCl. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MYCIFRADIN (MYCIFRADIN).
| Breastfeeding | Neomycin is excreted into breast milk in small amounts. The M/P ratio is approximately 0.5. Systemic absorption from topical application is minimal, but caution is advised with prolonged or extensive use due to potential for infant gut flora alteration and risk of sensitivity reactions. The American Academy of Pediatrics considers neomycin compatible with breastfeeding when used topically. For oral use, significant absorption is low, but caution is advised. Monitor infant for diarrhea or allergic reactions. |
| Teratogenic Risk | Neomycin (MYCIFRADIN) is classified as FDA Pregnancy Category D. There is evidence of fetal risk in animals and humans; however, potential benefits may warrant use in pregnant women despite potential risks. Neomycin is an aminoglycoside known to cause fetal nephrotoxicity and ototoxicity when administered systemically. However, topically applied neomycin has minimal systemic absorption, reducing fetal risk. First trimester risks include possible teratogenic effects, though data are limited. Second and third trimester risks include fetal ototoxicity and nephrotoxicity with significant maternal systemic absorption. Use only if clearly needed and when safer alternatives are unavailable. |
■ FDA Black Box Warning
Aminoglycosides can cause nephrotoxicity and ototoxicity (vestibular and auditory). The risk is increased with high doses, prolonged use, or in patients with renal impairment. Neuromuscular blockade and respiratory paralysis have been reported, especially with concurrent anesthetics or neuromuscular blocking agents.
| Serious Effects |
Hypersensitivity to neomycin (active component) or any aminoglycoside; intestinal obstruction; inflammatory or ulcerative gastrointestinal disease (risk of systemic absorption).
| Precautions | Monitor renal function (serum creatinine, BUN) and auditory function (audiometry) in prolonged therapy. Use with caution in patients with renal impairment, neuromuscular disorders (e.g., myasthenia gravis), or those receiving other nephrotoxic/ototoxic drugs. Avoid concurrent use with potent diuretics. |
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| Fetal Monitoring | Monitor maternal renal function (serum creatinine, BUN) and audiometry in prolonged or systemic use. For topical use, monitor for signs of systemic absorption (e.g., nephrotoxicity). Fetal monitoring should include ultrasound to assess for any signs of fetal distress or growth abnormalities if significant systemic exposure occurs. Assess for maternal ototoxicity with baseline and periodic audiograms. |
| Fertility Effects | Neomycin may impair fertility in males and females based on animal studies showing testicular degeneration and ovarian effects. In humans, data are limited; however, aminoglycosides can cause reversible infertility due to effects on sperm motility and ovarian function. Use with caution in patients planning conception. |