Tobramycin: Indications & How to Use (Drops & Ointment)

Tobramycin is an antibiotic medication that is indicated for the treatment of bacterial eye infections, like pink eye, keratitis or keratoconjunctivitis.

This medication can be purchased at a pharmacy with a prescription in the form of eye drops or ophthalmic ointment.

Tobramycin can be used by adults or children over 2 months of age and should only be used as prescribed, in the doses and for the duration indicated by your doctor.

What is it used for

Tobramycin is an antibiotic indicated for the treatment of bacterial eye infections. It can be used to treat:

• Conjunctivitis (pink eye)
• Blepharitis
• Blepharoconjunctivitis
• Keratitis
• Keratoconjunctivitis
• Dacryocystitis

The use of tobramycin should be guided and monitored by a doctor, as dosing and treatment duration depends on the condition being treated and its severity. 

It is important to note that tobramycin is only effective against bacterial infections, and does not treat eye infections caused by viruses or fungi.

How to use

Tobramycin should be applied to the affected eye/s and should not be ingested or injected. You should not wear contact lenses when applying it or during treatment.

Before applying tobramycin drops or cream, it is important to wash your hands with soap and water.

How tobramycin is applied depends on the form prescribed:

1. Tobramycin eye drops

Tobramycin in the form of ophthalmic drops should only be used in the affected eye. It is important to avoid touching the tip of the dropper bottle to your eyes to prevent contaminating the solution.

The normally recommended doses of tobramycin eye drops are:

• Mild to moderate eye infections: the normally recommended dose is 1 to 2 drops of tobramycin eye drops, in the affected eye, every 4 hours;
• Serious eye infections: the normally recommended dose is 2 drops of tobramycin eye drops, in the affected eye, every hour, until improvement is noted. If symptoms are lessening, the drops can start to be applied every 4 hours, or as advised by the ophthalmologist.

Tobramycin eye drops dosing should be reduced little by little, according to treatment response and as advised by a doctor.

To apply tobramycin eye drops, tilt your head back slightly and pull the lower eyelid down to expose a small pocket in the lower eyelid. Then hold the eye drop bottle above the eye with the tip facing down, look up and squeeze the bottle so that the drop falls into the affected eye.

After applying tobramycin eye drops, you should close your eye for 1 to 2 minutes, without blinking and press your finger gently on the inner corner of the eye, to prevent the eye drops from running into the tear duct.

If the dose recommended by the doctor is more than 1 drop, you should wait about 5 minutes between applying the drops.

Tobramycin eye drops should be stored at temperatures between 15º and 30ºC. Once opened, they are safe to use for 28 days and should be discarded after this period.

2. Tobramycin ointment

Tobramycin ophthalmic ointment should only be used in the affected eye. It is important to avoid touching the tip of ointment tube with your eyes to prevent contaminating it.

The normally recommended doses of tobramycin ointment are:

• Mild to moderate eye infections: the normally recommended dose is 1 centimeter of tobramycin ointment, in the affected eye, 2 to 3 times a day;
• Serious eye infections: the normally recommended dose is 1 centimeter of tobramycin ointment, in the affected eye, every 3 or 4 hours, until improvement is noted. Once symptoms start to lessen, the doctor can reduce the frequency of applications.

Tobramycin ointment should be reduced little by little, depending on the response to treatment, as supervised by an ophthalmologist.

To apply tobramycin ointment, tilt your head back slightly and pull the lower eyelid down to form a small pocket in the lower eyelid. Then hold the tube of ointment above the eye with the tip pointing downwards, towards the small pocket formed, look upwards and squeeze the tube so that the ointment is applied to the affected eye.

After applying tobramycin ointment, blink gently and close your eye for 1 to 2 minutes. When you open your eye again, your vision may become blurry or cloudy for a short period of time, which is considered normal.

Tobramycin ointment should be stored in a refrigerator, at temperatures between 2º and 8ºC. Avoid storing it in the refrigerator door, as constantly opening and closing the door can cause temperature variations in the ointment. Once opened, tobramycin ointment is safe to use for 28 days and should be discarded after this time.

Possible side effects

The most common side effect of tobramycin medications are itchy eyes, redness, burning, stinging, irritation, eyelid swelling, blurred vision or greater sensitivity to light and glare.

Tobramycin can also cause serious allergic reactions that require immediate medical attention. You should stop treatment and proceed to the nearest emergency room if you experience symptoms such as itching on your body, shortness of breath, feeling like your throat is closing, or swelling in your mouth, tongue or face. 

Contraindications for use

Tobramycin should not be used by newborns under 2 months of age, nor pregnant or breastfeeding women.

This medication should also not be used by people who are allergic to tobramycin or other antibiotics such as gentamicin, neomycin, streptomycin or vancomycin.

Tobramycin should not be applied while wearing contact lenses, and they should overall be avoided when undergoing treatment.