Gentamicin Side Effects

Not all side effects for gentamicin may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to gentamicin: injection injectable, injection solution

In addition to its needed effects, some unwanted effects may be caused by gentamicin. In the event that any of these side effects do occur, they may require medical attention.

If any of the following side effects occur while taking gentamicin, check with your doctor or nurse immediately:

Incidence not known
  • Abdominal or stomach cramps or pain
  • agitation
  • back pain
  • black, tarry stools
  • blood in the urine
  • blurred or double vision
  • burning, numbness, tingling, or painful sensations
  • change in frequency of urination or amount of urine
  • chest pain
  • chills
  • coma
  • confusion
  • continuing ringing or buzzing or other unexplained noise in the ears
  • cough
  • difficult or troubled breathing
  • difficulty with swallowing
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • drowsiness
  • dry mouth
  • eye pain
  • fast heartbeat
  • fever with or without chills
  • hallucinations
  • headache
  • hearing loss
  • hives
  • hoarseness
  • increased thirst
  • irregular heartbeats
  • irregular, fast or slow, or shallow breathing
  • irritability
  • itching
  • joint pain
  • loss of appetite
  • mood or mental changes
  • muscle cramps in the hands, arms, feet, legs, or face
  • muscle pain or weakness
  • muscle spasms (tetany) or twitching
  • nausea or vomiting
  • nervousness
  • numbness and tingling around the mouth, fingertips, or feet
  • pale or blue lips, fingernails, or skin
  • pale skin
  • pinpoint red spots on the skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • right upper abdominal or stomach pain and fullness
  • seizures
  • sensation of spinning
  • skin rash
  • slow or fast heartbeat
  • slow or irregular breathing
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • stiff neck
  • sweating
  • swelling of the feet or lower legs
  • swollen glands
  • tightness in the chest
  • trembling
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • weight chest discomfort
  • weight loss
  • wheezing

Some of the side effects that can occur with gentamicin may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

Incidence not known
  • Blurred or loss of vision
  • decreased appetite
  • depression
  • disturbed color perception
  • hair loss or thinning of the hair
  • halos around lights
  • hives or welts
  • increased salivation
  • night blindness
  • overbright appearance of lights
  • pain at the injection site
  • purple spots on the skin
  • redness of the skin
  • swelling or inflammation of the mouth
  • tunnel vision
  • unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness

For Healthcare Professionals

Applies to gentamicin: compounding powder, injectable solution, intravenous solution


The most frequently reported adverse effects associated with gentamicin therapy are ototoxicity and nephrotoxicity. These forms of toxicity occur more frequently in patients who experience prolonged exposure to serum gentamicin trough concentrations of greater than 2 mcg/mL. Patients with renal insufficiency are at an increased risk of developing toxicity.


Acute renal failure due to gentamicin is usually nonoliguric with an average rise in serum creatinine of 1 to 3 mg/dL. Renal function generally returns to baseline in 7 to 14 days. Rarely, gentamicin produces renal tubular acidosis and renal potassium and magnesium wasting. There is no relationship between acute renal failure and the daily dose of gentamicin, however, an increased incidence has been associated with a serum trough gentamicin concentration greater than 2 mcg/mL. It has been suggested that there is a correlation between the higher peak concentrations associated with once-daily dosing and a higher incidence of nephrotoxicity. Other predisposing factors include advanced age, preexisting renal insufficiency, dehydration, and concomitant use of other potentially nephrotoxic drugs.

Renal side effects associated with gentamicin use have included nephrotoxicity. The overall incidence of aminoglycoside nephrotoxicity is 2% to 10%. Gentamicin nephrotoxicity occurs in two forms: acute renal failure (ARF), and a more gradual, transient, and reversible azotemia. Fanconi syndrome and Bartter-like syndrome have been reported.

Nervous system

The onset of ototoxicity may be asymptomatic or may manifest as dizziness, vertigo, ataxia, tinnitus, and roaring in the ears. High tone hearing loss is often an early symptom of auditory toxicity. It has been suggested that once-daily dosing of gentamicin is associated with a higher incidence of ototoxicity.

Other side effects possibly related to gentamicin have included lethargy, confusion, depression, headache, pseudotumor cerebri, and acute organic brain syndrome.

Nervous system side effects have included ototoxicity, which generally presents as loss of vestibular function secondary to hair cell damage, but may also be auditory. Ototoxicity is closely related to the development of renal impairment, and may be irreversible. Peripheral neuropathy or encephalopathy with numbness, skin tingling, muscle twitching, seizures, and myasthenia gravis-like syndrome have also been reported.

Intraventricular and intrathecal administration of gentamicin has rarely been associated with aseptic meningitis, transient hearing loss, and seizures. Neuromuscular side effects including ataxia, paresis and incontinence have been reported after large intrathecal doses (40 mg to 160 mg) of preservative-containing gentamicin. Concurrent administration of parenteral and intrathecal gentamicin has been associated with eighth nerve dysfunction, fever, convulsions, leg cramps, and increases in cerebrospinal fluid protein.


Musculoskeletal side effects have rarely included neuromuscular blockade, which occurs most commonly in patients who are predisposed including patients with myasthenia gravis, hypocalcemia, and those receiving a concomitant neuromuscular blocking agent. Tetany and muscle weakness may be associated with gentamicin-induced hypomagnesemia, hypocalcemia, and hypokalemia. Joint pain has also been reported.


Respiratory side effects have included case reports of respiratory depression and respiratory arrest. Gentamicin has also been possibly associated with pulmonary fibrosis.


Hypersensitivity reactions possibly associated with gentamicin have included anaphylactoid reactions and laryngeal edema. Suspected allergic reactions against gentamicin with sodium metabisulfite preservative have been reported.


Local reactions have occasionally included pain at the injection site, and rarely subcutaneous atrophy or fat necrosis at the injection site. Reactions associated with intrathecal injections have included arachnoiditis and burning at the injection site.


Dermatologic side effects possibly associated with gentamicin have included rash, itching, urticaria, generalized burning, and alopecia.


Hematologic side effects possibly related to gentamicin use have included anemia, leukopenia, granulocytopenia, transient agranulocytosis, eosinophilia, increased and decreased reticulocyte counts, thrombocytopenia, immunologic thrombocytopenia, and purpura.


Hepatic side effects possibly related to gentamicin use have included transient hepatomegaly, and increases in serum transaminase, serum LDH, and bilirubin.


Cardiovascular side effects possibly related to gentamicin have included hypotension and hypertension.


Gastrointestinal side effects possibly related to gentamicin have included nausea, vomiting, weight loss, decreased appetite, increased salivation, and stomatitis.


Ocular side effects have included case reports of retinal ischemia resulting in loss of visual acuity after inadvertent intraocular injection of massive doses of gentamicin.


Other side effects possibly related to gentamicin have included transient splenomegaly and fever.

Pyrogenic reactions with symptoms of shaking, chills, fever, rigors, tachycardia, and/or hypotension have been reported with intravenous gentamicin. These reactions generally occurred within 3 hours of administration and were believed to be due to once-daily gentamicin doses delivering sufficient endotoxin over one hour to be pyrogenic.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.