Can't Find Tobrex? Here Are Your Options

When your doctor prescribes Tobrex (Tobramycin ophthalmic) for an eye infection and your pharmacy can't fill it, you need answers fast. Eye infections don't wait for supply chain issues to resolve. The good news is that several effective alternative antibiotic eye medications can treat the same types of infections.

In this article, we'll explain what Tobrex is, how it works, and walk you through the best alternatives your doctor may consider if Tobrex isn't available.

Important: Never switch medications on your own. Always talk to your doctor or eye care provider before using a different antibiotic. They'll choose the best option based on the type and severity of your infection.

What Is Tobrex and How Does It Work?

Tobrex is the brand name for Tobramycin ophthalmic solution and ointment (0.3%). It's an aminoglycoside antibiotic — a type of medication that kills bacteria by blocking their ability to make proteins. Without those proteins, the bacteria can't survive or multiply.

Doctors prescribe Tobrex for bacterial eye infections including:

• Bacterial conjunctivitis (pink eye)
• Keratitis (corneal infection)
• Corneal ulcers
• Blepharitis (eyelid infection)
• Blepharoconjunctivitis
• Dacryocystitis (tear duct infection)

Tobrex is particularly effective against gram-negative bacteria like Pseudomonas aeruginosa, Escherichia coli, and Klebsiella species, as well as some gram-positive organisms like Staphylococcus aureus.

For a deeper dive, see our article on how Tobrex works.

Alternative 1: Ciprofloxacin Ophthalmic (Ciloxan)

Ciprofloxacin ophthalmic, sold under the brand name Ciloxan, is a fluoroquinolone antibiotic available as both eye drops (0.3%) and ointment (0.3%). It's one of the most commonly prescribed alternatives to Tobrex.

How It Compares to Tobrex

• Spectrum: Ciprofloxacin covers a broad range of gram-negative and gram-positive bacteria, similar to Tobramycin. It's particularly effective against Pseudomonas species.
• Availability: Generic Ciprofloxacin ophthalmic is widely available and typically easier to find than Tobramycin during shortages.
• Cost: Generic Ciprofloxacin ophthalmic drops usually cost $10 to $30, making it comparable to or cheaper than generic Tobramycin.
• Dosing: Typically 1-2 drops every 2-4 hours for the first two days, then reduced as the infection improves.

Things to Know

Ciprofloxacin drops can sometimes leave a white crystalline deposit on the surface of the eye. This is harmless and resolves on its own, but it can be startling if you're not expecting it. The ointment form does not typically cause this issue.

Alternative 2: Moxifloxacin Ophthalmic (Vigamox)

Moxifloxacin ophthalmic, brand name Vigamox, is a newer-generation fluoroquinolone that has become a go-to choice for many eye care providers.

How It Compares to Tobrex

• Spectrum: Moxifloxacin has excellent broad-spectrum coverage including gram-positive organisms like Staphylococcus and Streptococcus species, as well as gram-negatives. Some consider it to have the best overall coverage among ophthalmic antibiotics.
• Convenience: Dosed just 3 times daily (compared to 4+ times for Tobramycin), which can improve adherence.
• No preservative issues: Vigamox is self-preserved (no benzalkonium chloride), making it gentler on the eye surface.
• Cost: Brand-name Vigamox can be expensive ($150 to $300+), but generic Moxifloxacin ophthalmic is available and typically costs $20 to $60.

Things to Know

Moxifloxacin is often the first choice for pre- and post-surgical eye infection prevention. If your doctor suggests this alternative, it's a well-established, highly effective option.

Alternative 3: Polymyxin B/Trimethoprim Ophthalmic (Polytrim)

Polytrim is a combination antibiotic eye drop containing Polymyxin B and Trimethoprim. It's been used for decades and remains one of the most commonly prescribed treatments for bacterial conjunctivitis.

How It Compares to Tobrex

• Spectrum: Good coverage against many common conjunctivitis-causing bacteria. Polymyxin B handles gram-negatives while Trimethoprim covers gram-positives, giving a broad combined spectrum.
• Availability: Generic Polytrim is widely available and rarely affected by shortages.
• Cost: One of the most affordable ophthalmic antibiotics — generic Polytrim typically costs $10 to $25.
• Dosing: Usually 1 drop every 3 hours (up to 6 doses per day) for 7-10 days.

Things to Know

Polytrim may not be the best choice for severe infections or corneal ulcers, where broader-spectrum coverage is preferred. It's most commonly used for straightforward bacterial conjunctivitis.

Alternative 4: Erythromycin Ophthalmic Ointment

Erythromycin ophthalmic ointment (0.5%) is a macrolide antibiotic that has been used for decades. It's best known for its use in newborns to prevent eye infections, but it's also prescribed for adults with mild to moderate bacterial eye infections.

How It Compares to Tobrex

• Spectrum: Covers many gram-positive bacteria well. Less effective against gram-negatives compared to Tobramycin.
• Form: Available only as an ointment, not drops. This means it will blur your vision temporarily after application.
• Cost: Very affordable — typically $8 to $20 for generic Erythromycin ophthalmic ointment.
• Dosing: Apply a small ribbon of ointment to the affected eye(s) up to 6 times daily.

Things to Know

Because Erythromycin has a narrower spectrum than Tobramycin, your doctor will likely reserve it for milder infections or situations where gram-positive bacteria are suspected. It's a good option when cost is a primary concern.

How to Talk to Your Doctor About Switching

If you can't find Tobrex or generic Tobramycin, here's how to have a productive conversation with your doctor:

1. Call the office and explain that your pharmacy cannot fill the Tobramycin prescription due to a shortage.
2. Ask about alternatives — mention the options above so your doctor knows you've done your homework.
3. Ask about severity — your doctor will consider the type of infection and which alternatives provide appropriate coverage.
4. Request the new prescription be sent directly to a pharmacy that has the alternative in stock. Use Medfinder to check availability first.

Final Thoughts

Not being able to fill your Tobrex prescription is frustrating, but it doesn't mean you have to go without treatment. Ciprofloxacin, Moxifloxacin, Polytrim, and Erythromycin are all proven antibiotic eye medications that your doctor can prescribe as alternatives.

The most important thing is to not delay treatment. Bacterial eye infections can worsen quickly and may lead to serious complications if left untreated. Contact your doctor as soon as you learn your prescription can't be filled.

To check if Tobrex or any of these alternatives are available near you, visit Medfinder. For more information on the Tobrex shortage, read our 2026 shortage update.