Loteprednol/tobramycin

The combination of loteprednol and tobramycin, loteprednol/tobramycin, is a prescription eye drop used to treat inflammation and bacterial infections in the eye. Loteprednol is an anti-inflammatory corticosteroid, and tobramycin is an antibiotic. Because it is a mixture of two drugs, loteprednol/tobramycin belongs to a class of eye medications known as "ophthalmic combinations". This combination of drugs is marketed by Baush & Lomb under the brand name Zylet. The Food and Drug Administration approved Zylet on December 14, 2004.

Loteprednol Structure; Source: NIH ^[1]

Other Names

Some other names for the combination of loteprednol with tobramycin include the following:

• tobramycin/loteprednol
• loteprednol etabonate/tobramycin

Uses

Loteprednol/tobramycin is used to treat inflammation and infection in the eye of adults under any of the circumstances below:

• the eye has a bacterial infection, or is at risk of developing one, and has inflammation that can be treated with steroids
• high risk of developing bacterial infection in the eye
• inflammation in the eye that responds to steroids

How Loteprednol/Tobramycin is Taken

Loteprednol/Tobramycin is dispensed in bottles containing 0.5% Loteprednol and 0.3% Tobramycin in a suspension for application into the eye(s). The recommended dose is one or two drops into the affected eye every four to six hours. If needed, drops can be applied every one to two hours for up to two days after starting treatment. The frequency is reduced gradually when the inflammation and/or infection improves.

How Loteprednol/Tobramycin Works

Tobramycin is a broad-spectrum antibiotic. It is an aminogycoside. Aminoglycoside antibiotics prevent bacteria from growing by inhibiting synthesis of proteins. They can also kill bacteria by increasing the permeability of the bacterial cell wall.

Loteprednol is a corticosteroid anti-inflammatory. The anti-inflammatory action of loteprednol is not well understood. However, corticosteroids like loteprednol are thought to act on proteins called lipocortins. These lipocortins control the synthesis of potent mediators of inflammation, such as prostaglandins and leukotrienes.

How the body affects loteprednol/tobramycin

Loteprednol/tobramycin is primarily metabolized in the eye into inactive forms. The corticosteroid component, loteprednol, does not enter the circulation to an appreciable extent.

Side Effects

Below are eye-related side effects reported in over 10% of patients enrolled in a clinical trial:

• eye redness
• death of cells on the surface of the cornea
• increased intraocular pressure
• burning and stinging upon application

Below are reactions that occurred with a frequency of less than 4%:

• vision disorders
• eye discharge
• itching
• tearing
• photophobia (sensitivity to light)
• corneal deposits
• eye discomfort
• eyelid disorders

Risks

Prolonged use of loteprednol/tobramycin carries some risks. Zylet could increase the pressure in the eye if it is taken for more than ten days. This pressure is caused by the buildup of the fluid in the eye. Doctors can measure the eye pressure to determine if it is elevated. As with other antibiotic preparations, prolonged use could also cause the overgrowth of organisms that are not susceptible to the antibiotic.

Allergic or hypersensitivity reactions could develop to the antibiotic component tobramycin. These reactions can be severe enough to warrant discontinuation of treatment. Sensitivity to one aminoglycoside confers sensitivity to all aminoglycoside antibiotics.

There are no adequate and well controlled studies of Zylet in pregnant women or nursing mothers. Some risk to the fetus or nursing infant exists.

Interactions

Loteprednol/tobramycin is very unlikely to interact with other drugs, especially drugs that are taken by mouth. To date, no drug interactions with loteprednol/tobramycin have been reported.

Alternatives

There are several ophthalmic combinations similar to Zylet available by prescription:

• neomycin/polymyxin/hydrocortisone (Cortisporin)
• polymycin b/trimethoprim (Polytrim)
• neomycin/polymyxin/dexamethasone (Maxitrol) *sulfacetamide sodium/fluorometholone (FML-S)
• neomycin/polymyxin/prednisolone (Poly Pred)
• gentamicine/prednisolone (Pred G)
• gentamicin/prednisolone (Pred G SOP)
• sulfacetamide sodium/prednisolone (Blephamide)
• tobramycin/dexamethasone (Tobradex)

Research

To date, three trials have examined the effectiveness or safety of loteprednol/tobramycin. Two of the trials compared the safety and effectiveness of loteprednol/tobramycin with another ophthalmic combination called dexamethasone/tobramycin in patients with inflammation of the margins of the eyelids, cornea, and conjunctiva (a condition known as "blepharokeratoconjunctivitis"). One of these studies found that loteprednol/tobramycin was equivalent or superior to dexamethasone/tobramycin in decreasing the signs and symptoms of the inflammation associated with blepharokeratoconjunctivitis. ^[2] However, patients treated with dexamethasone/tobramycin experienced a greater increase in interocular pressure than those treated with Zylet. In the other study, dexamethasone/tobramycin was more effective than loteprednol/tobramycin in reducing inflammation.^[3]

In the third study, the effect of loteprednol/tobramycin and dexamethasone/tobramycin on intraocular pressure were compared in healthy volunteers.^[4] Intraocular pressure was significantly increased in 2% of the volunteers given loteprednol/tobramycin and 7% of the volunteers given dexamethasone/tobramycin. Thus, the risk of developing elevated pressure in the eye may be lower for loteprednol/tobramycin than it is for some other drugs used to treat inflammation and infection.

References

1. ↑ http://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?id=3592&type=display
2. ↑ White EM, Macy JI, Bateman KM, Comstock TL. Comparison of the safety and efficacy of loteprednol 0.5%/tobramycin 0.3% with dexamethasone 0.1%/tobramycin 0.3% in the treatment of blepharokeratoconjunctivitis. Curr Med Res Opin. 2008 Jan;24(1):287-96. Abstract
3. ↑ Rhee SS, Mah FS. Comparison of tobramycin 0.3%/dexamethasone 0.1% and tobramycin 0.3%/loteprednol 0.5% in the management of blepharo-keratoconjunctivitis. Adv Ther. 2007 Jan-Feb;24(1):60-7. Abstract
4. ↑ Holland EJ, Bartlett JD, Paterno MR, Usner DW, Comstock TL. Effects of loteprednol/tobramycin versus dexamethasone/tobramycin on intraocular pressure in healthy volunteers. Cornea. 2008 Jan;27(1):50-5. Abstract

External Links

FDA: Zylet