Gentamicin

Pronunciation: jen-ta-MY-sin.

Generic name
gentamicin (as gentamicin sulfate)
Drug class
Aminoglycoside antibiotic
Form
Injection solution (10 mg/mL, 40 mg/mL, or 80 mg/2 mL depending on market); separately, topical/ophthalmic/otic solutions and ointments (e.g. 0.3% eye/ear drops, 0.1% topical cream/ointment) exist as genuinely different, non-boxed-warning products
Route
Intramuscular or intravenous injection (systemic form); topical, ophthalmic (eye), or otic (ear) for local infections
Legal status
Prescription-only, administered by or under the direction of a healthcare professional (injectable form); prescription or pharmacy-level for topical/ophthalmic/otic forms depending on country

Availability and supply rules vary by country

Trade names by country: United States · United Kingdom · Canada · Australia · New Zealand

Australia: Pfizer Gentamicin / DBL Gentamicin (7) · Full directory

What gentamicin (as gentamicin sulfate) is and how it works

Gentamicin is an aminoglycoside antibiotic used to treat serious bacterial infections, given by injection into a muscle or vein in a hospital or clinical setting, under close monitoring. A separate topical/ophthalmic/otic form treats local skin, eye, or ear infections. (1)

Because gentamicin injection carries a genuine, serious FDA boxed warning for kidney damage, usually-irreversible hearing/balance damage, and (less commonly) neuromuscular/breathing problems, it is only given under close medical supervision with regular blood tests and monitoring for hearing or balance changes. Never adjust your own dose or stop treatment without your care team's direction -- any concerns about hearing, balance, or reduced urination should be reported to your care team immediately.

Mechanism of action: how gentamicin (as gentamicin sulfate) works

Gentamicin is an aminoglycoside antibiotic that binds irreversibly to the bacterial 30S ribosomal subunit, causing misreading of mRNA and inhibiting bacterial protein synthesis, producing a bactericidal effect against many Gram-negative organisms and some Gram-positive organisms (often used synergistically with a beta-lactam or vancomycin for certain Gram-positive infections such as endocarditis). (1) (3)

What gentamicin (as gentamicin sulfate) is used for

Serious bacterial infections (injectable form)

Used to treat serious infections caused by susceptible bacteria, including bloodstream infections (septicaemia), urinary tract infections, respiratory tract infections, central nervous system infections, skin/bone/soft-tissue infections, complicated intra-abdominal infections, infective endocarditis, and infections in newborns. (1) (3)

Local eye or ear infections (topical/ophthalmic/otic form)

A separate, non-injectable gentamicin product treats local bacterial infections of the eye (such as conjunctivitis) or ear, applied directly rather than given systemically. (4)

Before taking gentamicin (as gentamicin sulfate)

Do not take / not appropriate for

  • Gentamicin should not be given to anyone with a known hypersensitivity to gentamicin, or a history of a serious toxic reaction to another aminoglycoside antibiotic, due to cross-sensitivity between this class of medicines. (all countries, injectable form) (1)
  • Some injectable formulations contain sodium metabisulfite, which can rarely cause severe allergic reactions (including anaphylaxis) in people who are sensitive to sulfites. (United States) (1)

Tell your clinician about

  • Any existing kidney problems, since these substantially raise the risk of gentamicin's kidney and hearing/balance toxicity.
  • Any history of hearing loss, tinnitus (ringing in the ears), or balance problems, or any family history of hearing loss linked to aminoglycoside antibiotics (this can indicate a genetic sensitivity).
  • Whether you have myasthenia gravis, Parkinson's disease, or another neuromuscular condition, since gentamicin can worsen muscle weakness in these conditions.
  • Whether you are pregnant, planning pregnancy, or breastfeeding.
  • All other medicines you are taking, especially other antibiotics that can affect the kidneys or hearing, potent diuretics, and any medicines used during anaesthesia or surgery.
(1) (3)

How to take gentamicin (as gentamicin sulfate)

  • Gentamicin injection is given by a healthcare professional into a muscle or a vein -- it is not a medicine you take or adjust yourself.
  • Your care team will check your kidney function and, where possible, your hearing before and during treatment, and will use blood tests to keep your gentamicin levels in a safe range.
  • Make sure you drink enough fluids (or receive adequate fluids if you cannot drink) during treatment, as directed by your care team, since dehydration increases the risk of kidney toxicity.
  • Topical/ophthalmic/otic gentamicin is applied to the affected eye, ear, or skin area exactly as directed by your clinician or the product label -- do not use it in ways not directed by your care team.
(1) (3)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6) (7) (8)

Missed dose

Gentamicin injection is administered by your care team on a set schedule as part of your treatment plan -- if a scheduled dose is delayed or missed, your care team will decide how to adjust your treatment. This is not a medicine you self-manage at home.

Overdose

Because gentamicin is given and monitored by a healthcare professional, overdose is managed by your care team through blood-level monitoring and supportive care, which may include stopping the medicine and providing kidney support if needed. If you or a caregiver are concerned about a possible dosing error, contact the treating clinical team or emergency services immediately. (1)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Nausea, vomiting.

What to notice: Nausea, vomiting.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Rash and fever.

What to notice: Rash and fever.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Injection-site reactions.

What to notice: Injection-site reactions.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (6)

Electrolyte disturbances (low potassium, calcium, or magnesium) picked up on blood tests.

What to notice: Electrolyte disturbances (low potassium, calcium, or magnesium) picked up on blood tests.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Serious warnings

Signs of kidney damage — boxed_warning

Symptoms: Reduced urination, swelling, or unusual tiredness -- often first detected through blood tests (rising creatinine or urea) rather than symptoms you would notice yourself.

Action: Your care team will monitor your kidney function with regular blood tests throughout treatment. Report any reduced urination or new swelling promptly so it can be assessed. (1)

Signs of hearing or balance damage — boxed_warning

Symptoms: Ringing in the ears (tinnitus), hearing loss (often high-frequency sounds first), dizziness, or unsteadiness.

Action: Tell your care team immediately if you notice any change in your hearing or balance -- this damage is usually irreversible, so early reporting matters. Your care team may arrange a hearing test (audiogram) during treatment. (1) (6)

Signs of neuromuscular blockade or breathing difficulty — boxed_warning

Symptoms: Unusual muscle weakness or difficulty breathing, particularly around the time of anaesthesia, surgery, or a large blood transfusion.

Action: Seek emergency medical help immediately if breathing difficulty occurs. This is a recognised, though less common, risk of gentamicin, especially alongside certain anaesthetic or muscle-relaxant medicines -- your surgical or anaesthesia team will be aware of this risk if you are having surgery. (1) (2)

Signs of a serious allergic reaction — emergency

Symptoms: Swelling of the face, lips, tongue, or throat; difficulty breathing; widespread rash or hives.

Action: Seek emergency medical help immediately. (1)

Interactions

  • Other medicines that can also harm the kidneys or hearing (such as cisplatin or certain other antibiotics) generally should not be given at the same time as gentamicin, since the risks can add up. (1)
  • Potent diuretics (water tablets) can themselves cause ototoxicity and may increase gentamicin's risk to hearing when used together. (1)
  • Anaesthetic medicines, non-depolarising muscle relaxants used during surgery, and large citrate-anticoagulated blood transfusions can increase the risk of neuromuscular blockade with gentamicin. (3) (2)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Gentamicin crosses the placenta and can cause fetal harm, including risk to the baby's hearing and kidneys. It is classified as Pregnancy Category D in the US labelling reviewed and is generally avoided in pregnancy unless the infection being treated is serious or life-threatening enough that your care team judges the benefit outweighs this risk. If gentamicin is used in pregnancy, the newborn's hearing and kidney function are typically monitored after birth. (1) (2) (3) (4) (5) (6) (7) (8)

Breastfeeding

Discuss breastfeeding with your care team if you are treated with gentamicin -- specific breastfeeding data was not detailed in the sources reviewed for this dossier. (1) (2) (3) (4) (5) (6) (7) (8)

Children

Gentamicin is used in children, including newborns, with dosing individualised by weight and age; monitoring for kidney and hearing/balance toxicity applies at every age. (1) (2) (3) (4) (5) (6) (7) (8)

Elderly

Older adults often have reduced kidney function, which raises the risk of gentamicin's kidney and hearing/balance toxicity -- dosing and monitoring are adjusted accordingly by the care team. (1) (2) (3) (4) (5) (6) (7) (8)

Hepatic_impairment

Not specifically detailed for gentamicin in the sources reviewed for this dossier -- gentamicin is primarily cleared by the kidneys rather than the liver. (1) (2) (3) (4) (5) (6) (7) (8)

Renal_impairment

Renal impairment is the single biggest risk factor for gentamicin's kidney and hearing/balance toxicity -- dosing is adjusted (often using creatinine-clearance-based tables) and levels are monitored closely in anyone with reduced kidney function. (1) (2) (3) (4) (5) (6) (7) (8)

Monitoring

Before starting

  • Baseline kidney function (creatinine/BUN)
  • Baseline hearing assessment where feasible
  • Body weight (for dose calculation)
  • Review of other nephrotoxic/ototoxic medicines

During treatment

  • Regular blood tests for kidney function and gentamicin drug levels (peak and trough) throughout treatment, especially if treatment continues beyond 5-7 days.
  • Monitoring for hearing changes (tinnitus, hearing loss) and balance problems, with audiological assessment if symptoms occur.
  • Fluid status and hydration, since dehydration increases kidney-toxicity risk.
(1) (3) (6)

Storage

Gentamicin injection is stored and handled by healthcare staff, typically below 25 degC and protected from light; injection ampoules are for single use only and any unused portion is discarded. Topical/ophthalmic/otic products should be stored as directed on their own labelling.

Study the drug class: Aminoglycosides

Professional information

Clinician-facing context only, sourced from the current US DailyMed prescribing information and the UK emc SmPC; verify against the current full label before prescribing or administering.

United States

Indication: Serious systemic bacterial infections

Dose summary: Children 6-7.5 mg/kg/day divided every 8 hours; infants/neonates 7.5 mg/kg/day divided every 8 hours; neonates =<1 week 5 mg/kg/day divided every 12 hours; target peak 4-10 mcg/mL (indication-dependent), trough <2 mcg/mL.

Renal context: Dose and/or interval adjusted based on renal function; serum levels and renal function monitored closely. (1)

United Kingdom / European Union

Indication: Serious systemic bacterial infections

Dose summary: Single daily dose (SDD/extended-interval) regimen preferred, 3-6 mg/kg/day for up to 7 days in adults, with age-banded paediatric/neonatal dosing.

Renal context: Dose adjusted using creatinine-clearance-based tables in renal impairment; levels monitored. (3)

Mechanism of action

Hepatic guidance

Gentamicin is renally eliminated with minimal hepatic metabolism; hepatic impairment is not a primary dose-adjustment factor in the sources reviewed.

Overdose note

Manage supportively with monitoring of renal function and serum gentamicin levels; haemodialysis can remove gentamicin from the circulation in cases of significant accumulation or overdose, under specialist direction. (1) (3)

Frequently asked questions

Does gentamicin have a boxed warning?

Yes. The injectable form of gentamicin carries a genuine, current FDA boxed warning covering kidney damage, usually-irreversible hearing and balance damage, neuromuscular blockade/breathing problems, and fetal-harm risk in pregnancy. This boxed warning applies to the injectable form; separate topical/ophthalmic/otic gentamicin products for local eye, ear, or skin infections do not carry this systemic boxed-warning content. (1)

Is the hearing damage from gentamicin permanent?

It can be. Multiple regulator sources (US, UK, Canada, New Zealand) describe gentamicin-related hearing and balance damage as usually irreversible, which is why hearing and balance are closely monitored during treatment and any changes are reported to your care team right away. (1) (6) (8)

Can gentamicin be used in pregnancy?

Gentamicin crosses the placenta and can potentially harm the unborn baby's hearing and kidneys, so it is generally avoided in pregnancy unless the infection being treated is serious enough that the care team judges the benefit outweighs this risk. If used, the newborn's hearing and kidney function are typically checked after birth. (1) (3)

What is the mechanism of action of gentamicin (as gentamicin sulfate)?

Gentamicin is an aminoglycoside antibiotic that binds irreversibly to the bacterial 30S ribosomal subunit, causing misreading of mRNA and inhibiting bacterial protein synthesis, producing a bactericidal effect against many Gram-negative organisms and some Gram-positive organisms (often used synergistically with a beta-lactam or vancomycin for certain Gram-positive infections such as endocarditis). (1) (3)

What is the generic name of Gentamicin?

The generic name is gentamicin (as gentamicin sulfate). (1) (4)

What class of drug is gentamicin (as gentamicin sulfate)?

Gentamicin is classed as: Aminoglycoside antibiotic. (1) (4)

References

  1. GENTAMICIN Injection, USP -- full prescribing informationU.S. Food and Drug Administration / DailyMed (NIH), full prescribing information · United States · accessed 2026-07-30 · source 1
  2. Gentamicin neuromuscular blockade/respiratory paralysis warning language (multiple manufacturer labels)Secondary pharmacy/clinical literature corroborating the neuromuscular blockade mechanism across multiple gentamicin injection labels · United States · accessed 2026-07-30 · source 2
  3. Gentamicin 40mg/ml Solution for Injection/Infusion -- Summary of Product Characteristicselectronic medicines compendium (emc), United Kingdom · United Kingdom · accessed 2026-07-30 · source 3
  4. Genticin (Gentamicin 0.3% w/v) Eye/Ear Drops -- Summary of Product Characteristicselectronic medicines compendium (emc), United Kingdom · United Kingdom · accessed 2026-07-30 · source 4
  5. Gentamicin (systemic use) -- list of nationally authorised medicinal products, PSUSA/00009159European Medicines Agency (EMA), list of nationally authorised medicinal products · European Union · accessed 2026-07-30 · source 5
  6. GENTAMICIN INJECTION USP -- Product MonographHealth Canada, Product Monograph · Canada · accessed 2026-07-30 · source 6
  7. GENTAMICIN 80mg/2mL (as sulfate) injection BP -- ARTG entries 11376 / 47268Therapeutic Goods Administration (TGA), Australia · Australia · accessed 2026-07-30 · source 7
  8. Gentamicin Injection -- New Zealand Data SheetMedsafe (New Zealand regulator) · New Zealand · accessed 2026-07-30 · source 8

Brand names by country

Single-ingredient gentamicin (as gentamicin sulfate) names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

  • Gentak3 mg/g · proficient rx lp
  • Gentamicin Sulfate Opth Solution3 mg/mL · direct_rx

United Kingdom

  • Gentamicin (generic, various strengths) / Cidomycin (3)MHRA licensed emc smpc confirmed injection · 10 mg/mL, 40 mg/mL, 80 mg/2 mL · various (e.g. Hameln)
  • Genticin (4)MHRA licensed emc smpc confirmed eyeear · 0.3% w/v · manufacturer per emc SmPC

Canada

  • DIOGENT
  • GENTAMICIN(E) 100MG LIQ IV
  • GENTAMICIN(E) 80MG LIQ IV
  • PMS-GENTAMICIN SULFATE OPH DPS

Australia

  • Pfizer Gentamicin / DBL Gentamicin (7)TGA ARTG registered confirmed · 80 mg/2 mL · Pfizer Australia Pty Ltd

New Zealand

  • Gentamicin Injection (generic) (8)Medsafe registered confirmed · 80 mg/2 mL · manufacturer per Medsafe data sheet
View brands in additional countries.

European Union

Gentamicin B. Braun / Gentamicin Sandoz (and other national generics) (5)

This page provides general reference information about gentamicin and is not a substitute for advice from the clinical team managing your treatment. Gentamicin injection carries a boxed warning for kidney, hearing/balance, and neuromuscular risks; all dosing, monitoring, and treatment decisions should be made with your care team.

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