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Overview: Gentamicin is an antibiotic for treating serious bacterial infections. It works by killing certain types of bacteria. Common side effects may include tiredness, reduced appetite, nausea, vomiting, or pain at the injection site. Contact your health care provider right away if you have trouble hearing or signs of kidney damage, such as not peeing as much as usual or swelling in your legs or feet. Gentamicin is given as an injection by a health care professional. 

Uses

What is gentamicin used for?

Gentamicin is an antibiotic that is commonly used to treat the following serious infections caused by certain bacteria.

  • Blood infections (septicemia)
  • Infections of the membranes surrounding the brain and spinal cord (meningitis)
  • Urinary tract infections (UTIs)
  • Lung infections (such as bronchitis or pneumonia)
  • Infections of the gastrointestinal (GI) tract 
  • Skin infections, including severe burns
  • Bone and joint infections
  • Infections of the heart and heart valves (endocarditis)

Gentamicin may not be the right medicine for some of the infections listed above, depending on which germs are causing the infection. Bacteria in some locations may have become resistant to gentamicin, which will make it not work as well.

Gentamicin may also be used for other conditions as determined by your health care provider.

How does gentamicin work (mechanism of action)?

Gentamicin kills certain types of bacteria by preventing them from making proteins.

How is gentamicin supplied (dosage forms)?

Gentamicin is available in an injectable form that is given by a health care provider.

For information on other dosage forms, see: 

How should I store gentamicin?

Gentamicin is usually given by a health care provider in a hospital or clinic. If you will store gentamicin at home, follow the instructions given by your health care provider.

Side Effects

What are the most common side effects of gentamicin?

The most common side effects of gentamicin are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Fatigue or tiredness
  • Decreased appetite or weight loss
  • Itching or rash
  • Fever or headache
  • Nausea or vomiting
  • Joint pain
  • Pain at the injection site

There may be other side effects of gentamicin that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of gentamicin?

While less common, the most serious side effects of gentamicin are described below, along with what to do if they happen.

Severe Allergic Reactions. Gentamicin may cause allergic reactions, which can be serious. Stop using gentamicin and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Kidney Damage. Kidney damage may happen with gentamicin. The risk of kidney damage is higher if gentamicin is used for longer periods of time or at higher doses. The risk is also higher in people who already have kidney problems. Tell your health care provider right away if you have any of the following symptoms of kidney damage.

  • Reduced need to pee
  • Swelling in your feet, ankles, or legs
  • Weakness or unusual tiredness
  • Trouble catching your breath or chest pain/pressure
  • Confusion
  • Nausea
  • Seizures

Nerve Damage. Nerves are the fibers that carry sensations from your body to the brain. Damage to nerves can happen in people who are using gentamicin. The risk of nerve damage is higher if gentamicin is used for longer periods of time or at higher doses. The risk is also higher in people with kidney problems. Tell your health care provider right away if you hear a ringing or roaring sound in your ears, feel dizzy, or have loss of hearing. Hearing loss may be permanent. Also tell your health care provider if you notice other symptoms of nerve damage, such as muscle twitching, tingling, or numbness.

Warnings & Precautions

Who should not use gentamicin?

Allergies to Ingredients. People who are allergic to any of the following should not use gentamicin.

  • Gentamicin
  • Any other medicine known as an aminoglycoside
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific gentamicin products they stock.

What should I know about gentamicin before using it?

Gentamicin is usually given by a health care provider in a hospital or clinic. 

If you store gentamicin at home, do not share it with other people, even if they have the same condition as you. It may harm them. Keep gentamicin out of the reach of children.

Throughout treatment, drink plenty of liquids and stay hydrated to reduce the risk of kidney problems.

What should I tell my health care provider before using gentamicin?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if gentamicin is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

Other Medicines and Supplements. Gentamicin may interact with other medicines and supplements. Before using gentamicin, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section below for more details.

Pregnancy. Gentamicin may cause harm to a fetus. Tell your health care provider if you are or plan to become pregnant. Your health care provider will let you know if you should use gentamicin while you are pregnant or trying to get pregnant.

Breastfeeding. It is not known if gentamicin passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should use gentamicin while breastfeeding.

Interactions

Does gentamicin interact with foods or drinks?

There are no known interactions between gentamicin and foods or drinks.

It is unknown if drinking alcohol will affect gentamicin.

Does gentamicin interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before using gentamicin.

  • A diuretic, also called a water pill, such as ethacrynic acid or furosemide, which is a medicine used to reduce edema (fluid retention) and blood pressure
  • Another antibiotic, such as a cephalosporin, polymyxin B, or another aminoglycoside, such as amikacin, tobramycin, or vancomycin
  • Cisplatin, which is a medicine used for treating cancer

This may not be a complete list of medicines that can interact with gentamicin. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much gentamicin?

If you or someone else has used too much gentamicin, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of gentamicin?

Gentamicin is usually given by a health care provider in a hospital or clinic. Your health care provider will make sure you are receiving gentamicin as scheduled.