Gentamicin (Otic)

Gentamicin is an antibiotic medication available in solution format for administration into the ear canal to fight infections of the ear.


What is Gentamicin?

Gentamicin is a broad spectrum antibiotic used to fight bacterial infections. Gentamicin is available in the form of ear drops to be administered in the ear canal to fight infections in the ear. This medication can also be administered intravenously or injected into a patient. It is also available in a topical format.

Because of the broad range of bacterium that it fights, Gentamicin may be used for the initial treatment of an infection for the first few days while testing is performed on the patient to determine the exact type of infection that they have. Patients who also have swelling in the infected ear may receive a combination medication of Gentamicin with a hydrocortisone medication as well.

How does Gentamicin work?

Gentamicin works by bonding with bacteria causing the infection, preventing the bacteria cells from manufacturing proteins in order to divide and grow. By stopping the growth of the bacteria, Gentamicin enables the body to fight off the infection.

Discovered in 1963, Gentamicin is derived from a bacteria strain known as micromonospora purpura. Gentamicin is on the WHO's list of essential medicines, which include the safest, most effective drugs in the world.

Conditions Treated

Type Of Medicine

  • Antibiotic

Side Effects

Patients who have experienced hypersensitivity to Gentamicin in the past or those who have had reactions to other medications, animals, dyes, preservatives or other items may be at risk of a reaction to this medication as well. Be sure to inform your doctor of any sensitivity that you've had to date.

You will be provided with a patient information handout that you should review prior to being treated with Gentamicin, asking any questions of your doctor or nurse to make sure you understand the process and the use of this medication.

Some patients have reported the following adverse effects after administering Gentamicin otic drops:

  • Red, swollen, itchy ear
  • Stinging, burning sensation in the ear

These symptoms may disappear over time, but should be reported to your physician right away to make sure you are safe to continue treatment with this drug.


Your prescription will be written especially for you by your doctor and should be followed completely as written. Do not lengthen your treatment time, increase your dosage amount or change the frequency you have been prescribed to take Gentamicin.

What your prescription reflects is the strength of the drug you are given, the health condition you have and other considerations that pertain to you. If you have any questions about what you have been prescribed, check with your physician or your pharmacist.

Ear drops

Adults and children over six years old who have been diagnosed with ear infections will most likely be directed to administer three to four drops in the ear that has been affected three different times each day. Use of this medication in children who are less than six years old must be determined to be appropriate by their physician.

To administer the drops:

  • Turn head or lie on your side with the infected ear up
  • Pull earlobe up and back in adult patients, down and back for pediatric patients, to align the ear canal
  • Drop in three to four drops of Gentamicin
  • Remain in this position for at least two minutes
  • Optional: insert sterile cotton into the ear opening to keep medicine in when you sit up
  • Do not touch the dropper to any surface
  • Keep the container of drops closed tightly
  • Continue your treatment until all medication is consumed

Even if your infection feels as though it has cleared and your symptoms are improved, continue to use the prescribed medication until it is gone or until your prescribed treatment duration is over, whichever comes first. Your course of treatment will typically last seven to ten days. If you do not feel that your condition has improved in this time, notify your doctor to determine if the course of treatment should be continued or altered.

Do not insert cotton swabs in your ear to clean them or to remove excess medication, as these could irritate your ear infection and cause damage or make it worse. Wipe the outside of the ear only with a tissue or clean cloth if any excess medication or discharge has appeared.

Missing a dose should not cause you to double dose this medication if it is close to the time when you would normally take your next set of drops. If you forgot a dose, take it as soon as you remember if it is still some time until your next dosage. Resume your regular dosing schedule as soon as possible.


Inform your physician if you have ever experienced sensitivity to antibiotic drugs such as Gentamicin. You will also need to remember to disclose any sensitive reactions you've had to foods, animals, preservatives, dyes or perfumes prior to being treated with Gentamicin.

Gentamicin has been determined to be appropriate for use in ear infections in pediatric patients who are older than six years of age. Use in younger patients than this has not been studied to determine if it is safe or effective for use.

Geriatric patients will most likely experience the same benefits of a course of treatment of Gentamicin as adult patients, though this age group may have age-related health concerns that would react differently to the medication. Use in this age group should be under doctor's advisement only.

Women who are pregnant or who may become pregnant should avoid using Gentamicin, as it could be absorbed into the placenta and harm your unborn child. Use of Gentamicin in pregnant women is under the advisement of a physician only.

Women who are breastfeeding have not been studied to determine if Gentamicin is safe to use with regard to passing it on to children via the breast milk. It may be advisable to temporarily discontinue breastfeeding while being treated with Gentamicin; consult your doctor or healthcare professional.

Not all medications are safe to use together, but Gentamicin will perhaps be prescribed with pain relief medications or anti-inflammatory drugs depending on the patient's need. For your own safety, do not take other medications while you are being treated with Gentamicin unless they are specifically approved by your physician. Inform your physician of other drugs that you are taking including those sold over the counter, vitamin and herbal supplements as well as holistic remedies.

Patients who have perforation or puncture injuries to their eardrums should not be treated with Gentamicin, as it could be absorbed too quickly and cause adverse health reactions that may be permanent.


Patients known to be hypersensitive to other antibiotics may also be adverse to Gentamicin use. High doses of this medication in patients who are intolerant to antibiotics or in children could cause adverse effects on health that are irreversible in nature. Dosage amount should be prescribed cautiously.

Women who are pregnant or those that may become pregnant should be made aware of the risks that use of this medication can pose to their unborn babies. Use of this medication on women who are pregnant is at the discretion of the physician and patient.

Women who are breastfeeding should also consider the possible risk of passing trace amounts of this medication on to their infants prior to allowing treatment with this medication. If possible, discontinue breastfeeding during your treatment with Gentamicin and for a short period of time after the course of treatment runs out.

Make sure you inform your physician if you have had ear problems in the past or if you currently have been diagnosed with a perforation or puncture injury to your eardrum. A course of treatment lasting longer than seven days will require a test of your hearing after your treatment with Gentamicin.

Discontinue use of Gentamicin and contact your physician immediately if you experience ringing in your ears, dizziness, and loss of hearing or difficulty moving. You may be hypersensitive to Gentamicin if you experience any itching, redness or rashes, swelling or discharge from your ear or difficulty breathing. These symptoms should also be reported to your doctor if you experience them.


Keep your prescribed amount of Gentamicin in the original packaging at room temperature, well away from light, moisture or heat exposure. Gentamicin, as with all other drugs, should be kept out of sight and reach of children and pets.

If you have expired Gentamicin or unused doses of this medication, consult with your doctor or pharmacist on the safest way to dispose of this drug. Never share this medication with other people even if they have the same condition as you.


Gentamicin is a broad spectrum antibiotic medication that is prescribed in different formats, including a liquid solution meant to be administered in the ear canal as drops. Patients are typically instructed to use three to four drops in the infected ear repeated three times per day. The course of treatment is typically seven to ten days. This medication is appropriate for adult patients, geriatric patients and patients who are older than six. Use in children younger than this is not recommended.

It is not recommended that Gentamicin is used on women who are pregnant or those who are breastfeeding, as it could be passed on to infants or children that will experience adverse health issues with this medication. Use of Gentamicin must be clearly required and determined to be appropriate by a physician in these groups.

Your physician will want to know if you have not had improvement in your symptoms by the time your medication has reached the end of the prescribed time or the amount you have been given.

If you experience any signs of hypersensitivity to this medication including rashes on the skin, swelling, redness or discharge from the ear or difficulty breathing, report these to your healthcare provider right away. Any ringing in your ears, dizzy feelings, muscle coordination loss or loss of hearing should also be reported right away.