AEROSPORIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AEROSPORIN (AEROSPORIN).
Polymyxin B binds to the lipid A portion of bacterial lipopolysaccharides, disrupting the outer membrane permeability and causing bacterial cell death. It is primarily active against Gram-negative bacteria.
| Metabolism | Primarily cleared by renal excretion with limited hepatic metabolism. |
| Excretion | Primarily renal excretion of unchanged drug via glomerular filtration. Approximately 60-70% of an intravenous dose is recovered in urine within 24 hours; minimal biliary/fecal elimination (<5%). |
| Half-life | Terminal elimination half-life is approximately 2-3 hours in adults with normal renal function; prolonged to 20-40 hours in severe renal impairment (CrCl <10 mL/min), necessitating dose adjustment. |
| Protein binding | Approximately 5-10% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | Vd is 0.2-0.4 L/kg, indicating distribution primarily in extracellular fluid; limited distribution into CSF, eye, and tissues. |
| Bioavailability | Intravenous: 100% (only route for systemic infections). Intramuscular: Approximately 70-80%. Oral: Negligible (<1%); not administered orally. Topical (ophthalmic): Minimal systemic absorption. |
| Onset of Action | Intravenous: Peak serum concentration achieved by end of infusion; clinical effect typically within 1-2 hours. Intramuscular: Onset within 1-2 hours. Topical (ophthalmic): Local effect within 15-30 minutes. |
| Duration of Action | Intravenous/Intramuscular: Duration of antimicrobial effect is approximately 8-12 hours, correlating with serum levels above MIC for susceptible organisms. Topical (ophthalmic): Duration of local action is 6-8 hours per application. |
| Molecular Weight | 1300.59 |
Polymyxin B sulfate: 1.5-2.5 mg/kg/day intravenously divided every 12 hours, or 25,000-30,000 units/kg/day intramuscularly divided every 12 hours. Ophthalmic: 1-2 drops in affected eye every 4 hours. Topical: Apply to affected area 3-4 times daily.
| Dosage form | INJECTABLE |
| Renal impairment | GFR 30-50 mL/min: Reduce dose by 50%; GFR <30 mL/min: Administer 1.5-2.5 mg/kg IV every 36-48 hours. Monitor serum levels and adjust based on toxicity. |
| Liver impairment | No specific Child-Pugh based recommendations; caution with severe impairment (Child-Pugh C) as excretion is renal. |
| Pediatric use | Neonates <2 kg: 4 mg/kg IV every 12 hours; Infants and children: 2.5-4 mg/kg/day IV divided every 6-12 hours, adjusted based on renal function. |
| Geriatric use | Start at lower end of dosing range due to age-related renal decline; monitor renal function and serum levels carefully (target trough <1-2 μg/mL). |
| 1st trimester | Avoid unless clearly needed. Polymyxin B is generally considered low risk but data limited. |
| 2nd trimester | Use with caution. No known teratogenicity. |
| 3rd trimester | Use with caution. Potential for nephrotoxicity in neonate if high maternal doses. |
Clinical note
Comprehensive clinical and safety monograph for AEROSPORIN (AEROSPORIN).
| Placental transfer | Polymyxin B crosses the placenta in limited amounts; data are sparse. |
| Breastfeeding | Excretion into breast milk is unknown. Use with caution; monitor infant for diarrhea or rash. |
| Lactation Rating | L3 (Moderately Safe) |
■ FDA Black Box Warning
Nephrotoxicity and neurotoxicity: Polymyxin B can cause acute renal failure, proteinuria, hematuria, and elevated BUN/creatinine. Neurotoxicity may include irritability, weakness, drowsiness, ataxia, perioral tingling, and respiratory paralysis. Use with caution in patients with renal impairment and monitor renal function closely.
| Serious Effects |
Hypersensitivity to polymyxin B or any component of the formulation
| Precautions | Monitor renal function and serum levels regularly, Avoid concurrent use of other nephrotoxic or neurotoxic drugs, Use with caution in patients with pre-existing renal disease, myasthenia gravis, or neuromuscular disorders, Respiratory paralysis may occur due to neuromuscular blockade; consider use of neostigmine as antidote, Intrathecal administration may cause meningeal irritation and dose-related side effects |
| Food/Dietary | No known food interactions. Avoid alcohol as it may exacerbate side effects if systemic absorption occurs. |
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| Teratogenic Risk | Topical AEROSPORIN (polymyxin B) is generally considered low risk for teratogenicity due to minimal systemic absorption. Animal studies have not shown fetal harm; no adequate human studies exist. Systemic administration in pregnancy is not recommended unless clearly needed. First trimester: theoretical risk from systemic exposure is very low. Second and third trimesters: no known fetal risks from topical use. |
| Fetal Monitoring | No specific monitoring required for topical use. If systemic absorption occurs (e.g., extensive application), monitor for nephrotoxicity and neurotoxicity in the mother. No fetal monitoring indicated. |
| Fertility Effects | No studies on fertility effects in humans. Animal studies have not reported adverse effects on fertility. Systemic absorption from topical use is minimal, making significant impact on fertility unlikely. |
| Clinical Pearls | AEROSPORIN (polymyxin B) is a topical antibiotic used for superficial infections; it has poor systemic absorption but can cause nephrotoxicity and neurotoxicity if applied to extensive burns or wounds. Avoid use on deep puncture wounds or serious burns. Combination with neomycin and bacitracin (e.g., Neosporin) is common for broader coverage. |
| Patient Advice | Apply a thin layer to affected area 2-3 times daily. · Do not use on large body surfaces or deep wounds without physician approval. · Discontinue if rash, swelling, or signs of allergy occur. · Keep out of eyes and mucous membranes. · Finish prescribed duration even if symptoms improve. |