The eyes are one of the most delicate organs in the body. They need constant hydration to prevent solid waste such as legumes and infections from forming.

Conjunctivitis is one of the most common diseases that can damage the organs of vision, which is why it is necessary to maintain the eyes properly and, if I know of an infection, effective treatment is necessary.

Among the treatments used to treat eye infections we have Tobradex and Tobrex, two drugs whose active component is tobramycin , which we will explain in depth in this article, their uses, effects and price.

What are Tobradex and Tobrex?

Tobrex is an antibiotic medicine, used for bacterial eye infections . Its main active component is tobramycin, an antibiotic of the aminoglycoside family whose function is to inhibit the protein synthesis of gram-negative bacteria.

Because tobramycin is a powerful and fast-acting substance, drugs made from this compound are widely used in clinical practice to combat eye infections.

One of the problems that can develop in the long run when using both Tobradex and Tobrex is that, due to the adaptive capacity of gram-negative bacteria, they present resistance to tobramycin , making the effect of these drugs diminish over time.

The main difference between Tobradex and Tobrex is its chemical composition. Tobradex is composed of tobramycin with a concentration of 3mg/ml and dexamethasone 1mg/ml. Dexamethasone is a powerful corticoid which is what makes Tobradex different from Tobrex since the latter does not contain it in its composition.

What are they used for?

Tobrex is used mainly to treat conjunctivitis, which is an inflammation of the conjunctive membrane , which is transparent and covers the eyes and part of the eyelids. The conjunctiva is made up of small blood vessels that cause the eye to turn red when they become inflamed.

Normally, conjunctivitis is not a bigger problem than discomfort in the eyes and that its appearance turns red, having a favorable evolution. It rarely degenerates into vision problems.

The causes of conjunctivitis can be varied, and may include allergies, pathogens such as mites, dust, pollen and solid residues of cosmetics and make-up. Another cause, which is combated by tobramycin products, is bacteria which, together with viruses, cause one third of diagnosed conjunctivitis.

Tobradex and Tobrex are indicated for other inflammatory processes (besides conjunctivitis) caused by bacteria.

Presentation and administration

Tobrex is marketed in the form of eye drops by the Novartis laboratories, in 5 ml vials with 3 mg/ml tobramycin concentration. Its administration is directly on the infected eye.

It is also marketed as an ointment , applied to the skin near the affected eye.

Both types of presentations can be given to children 12 months and older.

Tobradex is also marketed in the form of eye drops and ointments by Novartis laboratories. In the form of eyedrops it is presented as a combination of 1 mg/ml Dexamethasone and 3 mg/ml Tobramycin in a 5 ml bottle. It is recommended to use the drops every 4 or 6 hours. Tobradex in the form of an ointment can be combined with the eye drops, using the drops during the day and the ointment before going to sleep.


For mild problems, one or two drops of Tobrex eye drops are applied to the affected eye, every four hours . If the condition is greater, the recommendation is to apply two drops of the eye drops every hour and not to interrupt the treatment, but to prolong the applications until the treatment has been completed.

To avoid further infection, it is recommended that you clean your hands thoroughly before using the eye drop, store it in a cool, clean place, and keep it from touching other medicines. The drops should fall into the space between the eyeball and the eyelid.

In the case of Tobrex ointment the recommendation is to apply 1 cubic centimeter of the ointment to the infected eye two or three times a day in case it is mild. If the infection is serious, it is recommended to do it every three or four hours. The cream should fall into the space between the lower eyelid and the diseased eye.

Between the eyewash and the ointment, it should be noted that the latter is the one that causes less absorption of tobramycin, since it is applied on the cornea and the conjunctive membrane, two parts with low absorption capacity.

Mechanism of action

In the case of Tobradex, being a combination of tobramycin with dexamethasone, its mechanism of action involves the association of a corticosteroid that inhibits the inflammatory response with an aminoglycoside antibiotic of great potency and broad intervention spectrum. These substances act on bacterial cells, inhibiting protein synthesis.

Side effects

Tobrex can cause as main side effects itching, tearing, redness of the eye . Swelling of the conjunctiva and eyelid and hypersensitivity may also occur.

In the case of Tobradex, there may be, in addition to the effects of Tobrex, conjunctival erythema and glaucoma . If it is used for a long time, there may be an increase in pressure inside the eye, burning, itching, blurred vision, damage to the optic nerve, secondary eye infections and cataracts.


In pregnant and lactating women it is recommended to assess the risk-benefit ratio before starting treatment with tobramycin.

In both Tobrex and Tobradex treatments it is recommended to avoid wearing contact lenses during application and to wait about 20 minutes before reinserting them. It should be noted that because in conjunctivitis the eye is more sensitive and more vulnerable to other infections, it is recommended to avoid the use of contact lenses.

It is not recommended to operate heavy machinery or drive vehicles after applying the eye drops.

Its use is not recommended if you are suffering from any type of medical condition in which thinning of the cornea and sclera are present.

Prices of Tobrex and Tobradex

In Spain, the retail price of products made from tobramycin is quite affordable.

Tobrex ointment is sold in 3.5 g tubes, and costs 2.50 In the form of eye drops it costs about 1.81 euros.

Other products with the same active ingredient, such as Tobrabact and Tobrexan, sold in the form of eye drops, have similar prices.

Bibliographic references:

  • Palomino, J. & Pachón, J. (2003). Aminoglycosides. Infectious Diseases Clinical Microbiology, 21(2): 105-114.
  • Spanish Agency for Medicines and Healthcare Products (2005). Summary of product characteristics TOBREX Ophthalmic Ointment 3 mg/g ophthalmic ointment. Available at
  • Spanish Agency of Medicines and Health Products. (2005). TOBREX ophthalmic 3 mg/ml eye drops in solution. Vademecum. Available at
  • Vademecum (2018). TOBREX Eye drops in solution 3 mg/ml. Vademecum. Available at
  • Vademecum (2018). TOBRADEX Suspension eye drops 1 mg/ml + 3 mg/ml. Vademecum. Available at
  • Vademecum (2018). TOBRADEX ointment. Vademecum. Available at