From the FDA Drug Label
Caution should also be taken in concurrent or serial use of other amino-glycosides and polymyxins because they may enhance neomycin’s nephrotoxicity and/or ototoxicity and potentiate neomycin sulfate’s neuromuscular blocking effects. Concurrent and/or sequential systemic, oral or topical use of other aminoglycosides, including paromomycin and other potentially nephrotoxic and/or neurotoxic drugs such as bacitracin, cisplatin, vancomycin, amphotericin B, polymyxin B, colistin and viomycin, should be avoided because the toxicity may be additive.
The use of neomycin and polymyxin together may increase the risk of nephrotoxicity and/or ototoxicity.
- It is recommended to avoid concurrent or sequential use of these drugs due to the potential for additive toxicity 1, 1.
- The risk of neuromuscular blockage and respiratory paralysis may also be increased when neomycin is used with other neurotoxic and/or nephrotoxic drugs, including polymyxin.
- Cefdinir is not mentioned in the provided drug labels as interacting with neomycin or polymyxin.
- However, the combination of neomycin and polymyxin is not recommended due to the potential for increased toxicity.
From the Research
I strongly advise against taking neomycin, polymyxin, and cefdinir together without medical supervision due to the potential for increased risk of nephrotoxicity and other adverse effects. The combination of these medications can be harmful, particularly when taken orally, as both neomycin and cefdinir can affect kidney function, and polymyxin has been associated with nephrotoxicity in several studies 2, 3.
Potential Risks and Interactions
- Nephrotoxicity: The use of polymyxin has been linked to a higher risk of nephrotoxicity, with a pooled incidence of 45% (95% CI: 41-49%) in one systematic review and meta-analysis 3.
- Neurotoxicity: Although less common, neurotoxic effects of polymyxins can occur, including neuromuscular blockade, but recent studies suggest these effects are usually mild and resolve after discontinuation of the antibiotic 4.
- Antibiotic Resistance: Using multiple antibiotics without proper medical indication can contribute to antibiotic resistance, making it essential to use these medications judiciously.
Recommendations for Use
- Medical Supervision: It is crucial to consult a healthcare provider before combining any antibiotics to ensure safety and appropriate treatment for the specific condition.
- Topical vs. Oral Use: If neomycin/polymyxin is used topically (on skin, ears, or eyes) and cefdinir is taken orally as prescribed, this combination might be appropriate for treating different infections simultaneously under medical supervision.
- Monitoring and Dosing: Careful dosing, monitoring of kidney function, and avoidance of concurrent administration of nephrotoxic and/or neurotoxic drugs can help minimize the risk of adverse effects when using polymyxins 5, 4.