Neomycin Toxicity - Causes, Symptoms, and Treatment

What Is Neomycin?

Neomycin is an antibiotic medication that belongs to the class of aminoglycosides. It is frequently employed for the management of bacterial infections, especially those in the gastrointestinal tract. Neomycin works by inhibiting the synthesis of bacterial proteins, which prevents the bacteria from growing and spreading. As with other antibiotics in the aminoglycoside family, Neomycin is particularly efficient in eradicating gram-negative organisms, providing excellent coverage for enteric (intestine-related) bacteria. It is often used within the gastrointestinal tract because Neomycin is not well absorbed into the bloodstream.

What Are the Uses of Neomycin?

The US food and Drug Administration (FDA) has approved Neomycin for the treatment of hepatic encephalopathy or hepatic coma, particularly in acute cases than that for long-term use, due to its side effects. The other uses of this drug include the following:

• Perioperative or Surgical Prophylaxis: This requires combining Neomycin with Erythromycin or Metronidazole a day before surgery to decrease the possibility of surgical site infections.

• Skin Infections: Neomycin is a possible treatment option for bacterial skin infections such as impetigo and cellulitis.

• Eye Infections: Neomycin eye drops or ointment may be used to treat bacterial infections of the eye, such as conjunctivitis.

• Ear Infections: Neomycin may be used to treat bacterial infections of the ear, such as otitis externa.

• Prevention of Infections: Neomycin may be used to prevent infections in people with a high risk of developing them, such as those with weakened immune systems.

• Off-Label Usage: Neomycin is also used to treat constipation-predominant irritable bowel syndrome.

What Is Neomycin Toxicity?

Neomycin toxicity refers to the harmful effects that occur due to Neomycin intake. Although Neomycin is effective in treating bacterial infections, it can cause toxic effects in some individuals. The normal dose includes:

• The usual adult dose of Neomycin is 1 to 1.5 g (grams) per day, divided into three or four doses.

• The usual children's dose of Neomycin is 25 to 30 mg/kg (milligrams per kilogram) per day, divided into four doses.

Neomycin toxicity can occur at doses as low as 500 mg per day, especially in individuals with preexisting kidney or liver disease. Symptoms of Neomycin toxicity may appear at doses greater than 1 g per day, and severe toxicity may occur at doses greater than 12 g per day.

What Are the Causes of Neomycin Toxicity?

Several factors contribute to Neomycin toxicity which include:

• High Doses: If the drug is taken in high doses, it can accumulate in the body, leading to toxicity. Neomycin is usually prescribed in low doses to minimize the risk of toxicity.

• Prolonged Use: Neomycin is typically prescribed for short periods of time, usually less than two weeks. Prolonged use of the medication increases the chance of toxicity.

• Kidney or Liver Disease: Neomycin is eliminated from the body through the kidneys and liver. Patients with kidney or liver disease may be unable to eliminate the drug efficiently, and it accumulates within the body and develops toxicity.

• Drug Interactions: Neomycin may interact with other medications, leading to an increased risk of toxicity. Taking Neomycin with another medication that is metabolized by the liver or kidneys can increase the risk of toxicity.

What Are the Precautions to Be Taken When Using Neomycin?

Following are some precautions to be taken while using Neomycin:

• Neomycin should only be used under medical supervision and as prescribed by a healthcare provider.

• Avoid the use of Neomycin in individuals with a history of hypersensitivity to Neomycin or other aminoglycoside antibiotics.

• Use caution in individuals with kidney problems, hearing loss, or neuromuscular disorders.

• Long-term use of Neomycin should be avoided as it can increase the risk of toxicity.

• Monitor for potential side effects such as ringing in the ears, hearing loss, dizziness, nausea, vomiting, and diarrhea.

• Neomycin should be used with caution in children and elderly individuals due to the increased risk of adverse effects.

• Inform the healthcare professional of all medications and supplements being taken as Neomycin can interact with other medications, including certain diuretics, muscle relaxants, and anesthetics.

• It is advisable to refrain from using this medication while pregnant or nursing, as it has the potential to pass through the placenta and into breast milk.

What Are the Symptoms of Neomycin Toxicity?

Some common symptoms of Neomycin toxicity include:

• Nausea and vomiting.

• Diarrhea.

• Loss of appetite.

• Abdominal pain.

• Dehydration.

• Dizziness.

• Auditory impairment or tinnitus (a ringing sensation in the ears).

• Balance problems.

• Headache.

• Confusion.

• Muscle weakness or twitching.

• Kidney damage or failure.

How Can Neomycin Toxicity Be Diagnosed?

The diagnosis of Neomycin toxicity is done with the help of medical history, physical examination, and laboratory tests. The following are the steps for diagnosis:

• Blood Tests: Elevated Neomycin levels in the blood can be detected through blood tests. These tests also assess kidney function and electrolyte levels. It is recommended to obtain a baseline serum creatinine or BUN (blood urea nitrogen) to monitor any impact on renal function during chronic therapy and conduct periodic follow-up blood tests. Elderly patients may sometimes have impaired renal function, which routine screening tests such as BUN or serum creatinine may not detect. Therefore, it is more beneficial to determine creatinine clearance.

• Urine Tests: Urine tests can be used to assess kidney function and identify any signs of kidney damage.

• Hearing Tests: Hearing tests may be performed to assess any hearing loss or other auditory problems that may be associated with Neomycin toxicity.

• Imaging Tests: In some cases, imaging tests such as X-rays, CT (computed tomography) scans, or MRI (magnetic resonance imaging) may be ordered to assess the extent of any kidney damage or other complications.

What Is the Treatment for Neomycin Toxicity?

Neomycin toxicity can be treated in the following ways:

• Stopping Drug Intake: The first step in managing Neomycin toxicity is to discontinue the medication. This allows the body to eliminate the drug and prevent further damage.

• Supportive Care: Supportive care may be necessary to manage symptoms and prevent complications. This may include rehydration, nutritional support, and electrolyte replacement.

• Monitoring for Complications: Patients with Neomycin toxicity may be at risk of developing complications such as kidney damage or hearing loss. Regular monitoring for these complications may be necessary to prevent further damage and guide appropriate treatment.

• Medication Adjustment: In some cases, medication adjustment may be necessary to manage Neomycin toxicity. This may involve reducing the dose or switching to an alternative medication.

• Complications Management: If complications such as kidney damage or hearing loss develop, appropriate treatment may be necessary. This may involve medication, surgery, or other interventions.

• Prevention: Prevention of Neomycin toxicity involves careful monitoring and appropriate use of the medication. This may include avoiding high doses, limiting the duration of treatment, and monitoring drug interactions.

Conclusion

Neomycin toxicity is not very common, but it is necessary to closely monitor for any signs of toxicity when taking this medication, especially in individuals with preexisting health conditions or who are taking other medications that may increase the risk of toxicity. In certain instances, it may be essential to perform periodic checks on kidney function and electrolyte levels to prevent toxicity. If any signs of toxicity occur, inform a healthcare professional as early as possible.