Neomycin is an antibiotic medication used to treat and prevent bacterial infections. It belongs to a class of antibiotics known as aminoglycosides. This medication works by stopping the growth of certain bacteria.
How Neomycin Works
Neomycin interferes with bacterial protein synthesis, a process essential for bacterial survival. It specifically binds to the 30S ribosomal subunit within bacterial cells. This binding causes bacteria to misread their genetic code, leading to faulty or non-functional proteins.
The disruption of protein synthesis prevents bacteria from growing and multiplying, ultimately leading to their death. Neomycin is effective against a broad spectrum of bacteria, including various Gram-negative and some Gram-positive organisms.
Common Applications of Neomycin
Neomycin is commonly used in several forms, primarily for localized infections due to its poor absorption into the bloodstream when taken orally. It is frequently found in topical preparations for skin infections, such as minor cuts, scrapes, and burns. These topical forms often combine neomycin with other antibiotics like polymyxin B and bacitracin, as seen in products like Neosporin, to provide broader coverage.
For eye and ear infections, neomycin is available in ophthalmic solutions and otic suspensions. In these applications, it is often combined with other agents, such as polymyxin B and hydrocortisone or dexamethasone, to address both bacterial infection and inflammation. For instance, in swimmer’s ear, neomycin helps eliminate bacterial growth in the ear canal.
Oral neomycin is used to reduce the number of bacteria in the gut. This application is common before bowel surgery to lower the risk of postoperative infections. It is also prescribed to manage hepatic encephalopathy, a liver condition where harmful toxins build up due to excessive gut bacteria. By reducing ammonia-producing bacteria, neomycin helps alleviate neurological symptoms.
Important Safety Information for Neomycin Use
Despite its effectiveness, neomycin carries important safety considerations, particularly concerning potential side effects. Two serious adverse effects are damage to the inner ear (ototoxicity), leading to hearing loss or balance problems, and kidney damage (nephrotoxicity). These side effects are more likely with systemic absorption, higher doses, or prolonged use, and can occur even in patients with normal kidney function.
Common, less severe side effects for topical use may include allergic reactions, skin irritation, redness, or itching at the application site. Patients should avoid applying neomycin to large areas of broken skin, deep wounds, or serious burns, as this can increase systemic absorption and the risk of toxicity.
Healthcare providers advise caution when using neomycin, especially for pregnant or breastfeeding individuals, or those with existing kidney impairment, as these factors can increase the risk of toxicity. Concurrent use of other medications that can cause kidney or ear damage, such as certain diuretics or other aminoglycosides, should be avoided or carefully monitored due to additive toxicity. Prolonged use of neomycin, even topically, should be avoided as it can promote bacterial resistance and increase the risk of overgrowth by non-susceptible organisms, including fungi.