Why Is Polymyxin B/Trimethoprim So Hard to Find? [Explained for 2026]

If you've ever walked into a pharmacy with a prescription for Polymyxin B/Trimethoprim eye drops — sold under the brand name Polytrim — and walked out empty-handed, you're not alone. This widely used antibiotic eye drop has seen spotty availability at some pharmacies, leaving patients frustrated and providers scrambling for alternatives. In this article, we break down exactly why this happens and what you can do about it.

What Is Polymyxin B/Trimethoprim (Polytrim)?

Polymyxin B/Trimethoprim ophthalmic solution — most commonly known by its brand name Polytrim — is a prescription antibiotic eye drop approved by the FDA in October 1988 to treat bacterial conjunctivitis (pink eye) and blepharoconjunctivitis. It combines two antibiotics into a single sterile solution: polymyxin B sulfate (10,000 units/mL) and trimethoprim (1 mg/mL). It's approved for adults and children as young as 2 months of age, making it one of the broadest-use antibiotic eye drops available.

For decades, Polytrim has been a staple first-line treatment for mild to moderate bacterial eye infections due to its effectiveness, tolerability, and relatively low cost. Generics are widely available and typically cost far less than newer fluoroquinolone alternatives.

Why Was Polymyxin B/Trimethoprim Hard to Find?

The primary cause of supply disruptions for Polymyxin B/Trimethoprim eye drops traces directly to a single major event: Akorn, Inc., one of the leading manufacturers of generic ophthalmic medications in the United States, ceased all operations in February 2023. Akorn had been a major supplier of Polymyxin B/Trimethoprim ophthalmic solution, and its sudden exit from the market created a meaningful gap in supply.

Greenstone (a Viatris subsidiary) also discontinued their formulation around the same time, removing yet another supplier from the market. When multiple generic manufacturers exit simultaneously, pharmacies — particularly independent and smaller chain locations — can face prolonged back-order situations. The American Society of Health-System Pharmacists (ASHP) formally documented this shortage beginning in March 2023.

Is the Shortage Still Happening in 2026?

The good news: as of late 2024 and into 2026, the worst of the disruption has eased. Two major manufacturers — Bausch Health (Bausch + Lomb) and Sandoz — stepped in to fill the supply gap. The ASHP updated its shortage entry in November 2024 to reflect that both companies have product available. However, pharmacy-level stocking varies significantly. Not every pharmacy carries every manufacturer's version, and wholesaler allocations can still result in individual pharmacies being temporarily out of stock.

In plain terms: the drug exists and is being made — but finding it at your specific pharmacy on a given day can still be a challenge. Chain pharmacies may have inconsistent stock, and smaller independent pharmacies may not carry it at all if they haven't updated their ordering.

Why Does Pharmacy-Level Stock Vary So Much?

Even when a drug is nationally available, individual pharmacy stock depends on several factors:

Wholesaler contracts: Not all pharmacies buy from the same wholesaler, and a wholesaler may only carry one manufacturer's version.

Demand fluctuations: Conjunctivitis season (winter and spring) creates spikes in demand that outpace normal ordering cycles.

Low margin: Generic ophthalmic drops carry thin profit margins, so some pharmacies deprioritize stocking them deeply.

Small bottle size: A 10 mL bottle is easily oversold during a surge without the pharmacy noticing before the next order cycle.

What Should You Do If Your Pharmacy Doesn't Have It?

If one pharmacy doesn't have Polymyxin B/Trimethoprim in stock, don't give up. Here are your best next steps:

Use medfinder — medfinder.com calls pharmacies near you to check real-time stock, so you don't have to make a dozen calls yourself.

Try independent pharmacies — Independent and compounding pharmacies often maintain different inventory than chain pharmacies and may have stock when big chains don't.

Ask about the alternative manufacturer — If your pharmacy carries Bausch but not Sandoz, ask them to check with their wholesaler for the other brand, or call a pharmacy that may carry a different supplier.

Ask your doctor about alternatives — If Polytrim is truly unavailable at any nearby pharmacy, a fluoroquinolone eye drop such as ciprofloxacin or moxifloxacin may be prescribed instead.

Is Polymyxin B/Trimethoprim the Same as Polytrim?

Yes — Polytrim is the brand name for polymyxin B sulfate/trimethoprim sulfate ophthalmic solution. When your doctor prescribes Polytrim, a pharmacist may dispense the generic version from Bausch or Sandoz. If your pharmacy is out of one, ask specifically whether the other generic version is available. They are therapeutically equivalent.

The Bottom Line

Polymyxin B/Trimethoprim's supply challenges stem directly from major manufacturer exits in 2023, but the market has largely stabilized. Your best bet in 2026 is to shop around and use tools that find available stock for you. Read more about how to find Polymyxin B/Trimethoprim in stock near you for a step-by-step guide.

If your pharmacy can't fill the prescription at all, see our guide to alternatives to Polymyxin B/Trimethoprim for options your doctor may consider.