Neomycin PO

Reviewed on 12/29/2022

What Is Neomycin PO and How Does It Work?

Neomycin PO is a prescription medication used to decrease the risk of infection after certain intestinal surgeries. It is also used for hepatic encephalopathy and diarrhea caused by enteropathogenic E.coli.

  • Neomycin PO is available under the following different brand names: Neo-Fradin, Myciguent, Mycifradin

What Are Side Effects Associated with Using Neomycin PO?

Common side effects of Neomycin PO include:

  • Nausea,
  • Vomiting, or
  • Diarrhea.

Serious side effects of Neomycin PO include:

  • Drowsiness,
  • Confusion,
  • Mood changes,
  • Increased thirst,
  • Loss of appetite,
  • Weight gain,
  • Shortness of breath,
  • Shallow breathing,
  • Hearing problems,
  • Spinning sensation,
  • Feeling of passing out,
  • Loss of balance or coordination,
  • Trouble walking,
  • Numbness or tingly feeling under the skin,
  • Muscle twitching,
  • Seizures (convulsions),
  • Urinating less than usual or not at all,
  • Swelling,
  • Severe stomach cramps, or
  • Watery or bloody diarrhea.

Rare side effects of Neomycin PO include:

  • none 

Seek medical care or call 911 at once if you have the following serious side effects:

  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Are the Dosages of Neomycin PO?

Adult and pediatric dosage


  • 500 mg
  • Oral solution
  • 25 mg/mL

Pre-Op Intestinal Antisepsis

Adult dosage

  • 1 g orally at 19-, 18-, and 9 hours pre-op OR
  • 1 g orally every 1 hour for 4 doses, then 1 g every 4 hours to complete 24 hours of dosing OR
  • 88 mg/kg/day d4 hours orally every 4 hours for 2-3 days pre-op  
  • Maximum: Up to 12 grams 24 to 48 hours before surgery

Hepatic Encephalopathy

Adult dosage

  • Acute: 4-12 g/day orally divided every 6 hours for 5-6 days OR 3-6 g/day for 1-2 weeks
  • Chronic: Up to 4 g/day orally

Pediatric dosage

  • Hepatic encephalopathy: 50-100 mg/kg/day orally divided every 8 hours for 5-6 days, no more than 12 g/24 hours

Diarrhea Caused by Enteropathogenic E. coli

Adult dosage

  • 3 g/day orally divided every 6 hours
  • Pediatric dosage
  • 50mg/kg/day orally divided every 6 hours for 2-3 days

Bowel preparation

Pediatric dosage

  • 90 mg/kg/day orally divided every 4 hours for 2-3 days

Dosage Considerations – Should be Given as Follows

  • See “Dosages”

What Other Drugs Interact with Neomycin PO?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first

  • Neomycin PO has severe interactions with the following drugs:
  • Neomycin PO has serious interactions with at least 25 other drugs.
  • Neomycin PO has moderate interactions with at least 66 other drugs.
  • Neomycin PO has minor interactions with at least 65 other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Neomycin PO?


  • Hypersensitivity
  • Patients with a history of hypersensitivity or serious toxic reactions to other aminoglycosides
  • Patients with inflammatory or ulcerative gastrointestinal disease

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Neomycin PO?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Neomycin PO?”


  • Potential for enhanced gastrointestinal absorption of neomycin in patients with inflammatory or ulcerative gastrointestinal disease; use is contraindicated
  • Risks of hearing loss continue after drug withdrawal
  • Aminoglycoside antibiotics cross the placenta; there have been several reports of total irreversible bilateral congenital deafness in children whose mothers received streptomycin during pregnancy
  • Prescribing this antibiotic in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of development of drug-resistant bacteria
  • Use of this drug may result in the overgrowth of non-susceptible organisms, particularly fungi; if this occurs, appropriate therapy should be instituted
  • Neomycin is quickly and almost totally absorbed from body surfaces (except the urinary bladder) after local irrigation and when applied topically in association with surgical procedures
  • Delayed-onset, irreversible deafness, renal failure, and death due to neuromuscular blockade (regardless of the status of renal function) were reported following irrigation of both small and large surgical fields with minute quantities of neomycin
  • Cross-allergenicity among aminoglycosides has been demonstrated; aminoglycosides should be used with caution in patients with muscular disorders such as myasthenia gravis or parkinsonism since these drugs may aggravate muscle weakness because of their potential curare-like effect on neuromuscular junction
  • Small amounts of orally administered neomycin are absorbed through intact intestinal mucosa; there have been many reports in the literature of nephrotoxicity and/or ototoxicity with oral use of neomycin
  • If renal insufficiency develops during oral therapy, consider reducing the drug dosage or discontinuing therapy
  • An oral neomycin dose of 12 g/day produces malabsorption syndrome for various substances including fat, nitrogen, cholesterol, carotene, glucose, xylose, lactose, sodium, calcium, cyanocobalamin, and iron.
  • Orally administered neomycin increases fecal bile acid excretion and reduces intestinal lactase activity

Pregnancy and Lactation

  • Although serious side effects to fetus or newborn have not been reported in the treatment of pregnant women with other aminoglycosides, the potential for harm exists


  • Not known whether neomycin is excreted in human milk but shown to be excreted in cow milk following a single intramuscular injection; other aminoglycosides are excreted in human milk
  • Because of the potential for serious adverse reactions from aminoglycosides in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, considering the importance of the drug to the mother

Health Solutions From Our Sponsors