Last updated on RxList: 11/7/2022

Drug Summary

What Is Gentak?

Gentak (gentamicin sulfate) Ophthalmic Ointment is an antibiotic used to treat bacterial infections of the eyes. Gentak Ophthalmic Ointment is available in generic form.

What Are Side Effects of Gentak?

Gentak may cause serious side effects including:

  • hives,
  • difficulty breathing,
  • swelling of your face, lips, tongue, or throat,
  • severe burning, stinging, or irritation after using the medicine,
  • signs of eye infection (pain, swelling, severe discomfort, crusting or drainage), and
  • increased sensitivity to light

Get medical help right away, if you have any of the symptoms listed above.

Common side effects of Gentak Ophthalmic Ointment include:

  • eye burning,
  • stinging,
  • irritation,
  • itching,
  • redness,
  • blurred vision,
  • eyelid itching,
  • eyelid swelling, or
  • sensitivity to light.

Use of Gentak for prolonged or repeated periods may result in other types of eye infections, including fungal infections. Tell your doctor if you notice new or worsening eye symptoms (such as pain, swelling, thick discharge or pus).

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

  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in your chest; shortness of breath; and sudden dizziness, lightheadedness, or passing out;
  • 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.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

Dosage for Gentak

The recommended dose of Gentak is a small amount (approximately 1/2 inch ribbon) of ointment applied to the affected eye(s) two or three times a day. Do not use other eye drops or medications during treatment with Gentak ophthalmic unless directed by your doctor.

What Drugs, Substances, or Supplements Interact with Gentak?

Other drugs may interact with Gentak ophthalmic. Tell your doctor all medications and supplements you use.

Gentak During Pregnancy or Breastfeeding

Tell your doctor if you are pregnant or plan to become pregnant before using Gentak ophthalmic; it is unknown if it will harm a fetus. It is unknown if Gentak ophthalmic passes into breast milk. Consult your doctor before breastfeeding.

Additional Information

Our Gentak (gentamicin sulfate) Ophthalmic Ointment Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

Drug Description


GENTAK® Gentamicin sulfate is a water soluble antibiotic of the aminoglycoside group.

Gentamicin sulfate ophthalmic ointment is a sterile ointment for ophthalmic use. Each gram contains gentamicin sulfate equivalent to 3 mg gentamicin in a base of white petrolatum and mineral oil, with methylparaben and propylparaben as preservatives.

Gentamicin is obtained from cultures of Micromonospora purpurea. It is a mixture of the sulfate salts of gentamicin C1, C2, and C1A. All three components appear to have similar antimicrobial activities. Gentamicin sulfate occurs as a white to buff powder and is soluble in water and insoluble in alcohol. The structural formula is as follows:

 GENTAK® (Gentamicin Sulfate) Structural Formula Illustration

Indications & Dosage


Gentamicin sulfate ophthalmic ointment is indicated in the topical treatment of ocular bacterial infections including conjunctivitis, keratitis, keratoconjunctivitis, corneal ulcers, blepharitis, blepharonconjunctivitis, acute meibomianitis, and dacryocystitis, caused by susceptible strains of the following microorganisms:

Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus pneumoniae, Enterobacter aerogenes, Escherichia coli, Haemophilus influenzae, Klebsiella pneumoniae, Neisseria gonorrhoeae, Pseudomonas aeruginosa, and Serratia marcescens.


Apply a small amount (approximately 1/2 inch ribbon) of ointment to the affected eye(s) two or three times a day.


GENTAK® Gentamicin sulfate ophthalmic ointment USP, 0.3% is supplied in 3.5 g tube, box of one.
(NDC 17478-284-35)


Store at 2° to 30°C (36° to 86°F).

Manufactured by: Akorn, Inc., Lake Forest, IL 60045. Rev. 09/08.

Side Effects & Drug Interactions


Bacterial and fungal corneal ulcers have developed during treatment with gentamicin ophthalmic preparations.

The most frequently reported adverse reactions are ocular burning and irritation upon drug instillation, non-specific conjunctivitis, conjunctival epithelial defects and conjunctival hyperemia.

Other adverse reactions which have occurred rarely are allergic reactions, thrombocytopenic purpura and hallucinations.


No information provided.

Warnings & Precautions



Gentamicin sulfate ophthalmic ointment is not for injection. It should never be injected subconjunctivally, nor should it be directly introduced into the anterior chamber of the eye.



Prolonged use of topical antibiotics may give rise to overgrowth of nonsusceptible organisms including fungi. Bacterial resistance to gentamicin may also develop. If purulent discharge, inflammation or pain becomes aggravated, the patient should discontinue use of the medication and consult a physician.

If irritation or hypersensitivity to any component of the drug develops, the patient should discontinue use of this preparation and appropriate therapy should be instituted.

Ophthalmic ointments may retard corneal healing.

Carcinogenesis, Mutagenesis, Impairment of Fertility

There are no published carcinogenicity or impairment of fertility studies on gentamicin. Aminoglycoside antibiotics have been found to be non-mutagenic.


Pregnancy Category C. Gentamicin has been shown to depress body weights, kidney weights and median glomerular counts in newborn rats when administered systemically to pregnant rats in daily doses approximately 500 times the maximum recommended ophthalmic human dose. There are no adequate and well-controlled studies in pregnant women. Gentamicin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Pediatric Use

Safety and effectiveness in neonates have not been established.

Overdose & Contraindications


No information provided.


Gentamicin sulfate ophthalmic ointment is contraindicated in patients with known hypersensitivity to any of the components.

Clinical Pharmacology



Gentamicin sulfate is active in vitro against many strains of the following microorganisms:

Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus pneumoniae, Enterobacter aerogenes, Escherichia coli, Haemophilus influenzae, Klebsiella pneumoniae, Neisseria gonorrhoeae, Pseudomonas aeruginosa, and Serratia marcescens.

Medication Guide


To avoid contamination, do not touch tip of container to the eye, eyelid or any surface.

FDA Logo

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.