Why Is Colistin So Hard to Find? [Explained for 2026]

Why Is Colistin So Hard to Find?

If your doctor prescribed Colistin — also known as Colistimethate Sodium or by its brand name Coly-Mycin M — you may have already discovered that finding it in stock is far from simple. Pharmacies are turning patients away, hospitals are rationing supply, and nobody seems to have clear answers.

You're not imagining the problem. Colistin has become one of the hardest antibiotics to find in the United States, and the situation in 2026 remains challenging. In this post, we'll explain exactly why Colistin is so difficult to locate and what steps you can take to get the treatment you need.

What Is Colistin?

Colistin is a polymyxin antibiotic (also called Polymyxin E) that has been around since the 1950s. It works by binding to the outer membranes of gram-negative bacteria and destroying them from the outside in. For decades, doctors stopped prescribing it because newer, less toxic antibiotics were available.

But here's the twist: as antibiotic resistance has surged worldwide, many of those newer drugs stopped working against dangerous bacteria like Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae. Colistin has become a last-resort antibiotic — the final option when nothing else works.

It is administered intravenously (IV) or intramuscularly (IM) in hospital settings, and sometimes used off-label as an inhaled treatment for cystic fibrosis patients with chronic Pseudomonas infections. You can learn more about how the drug works in our guide: How Does Colistin Work? Mechanism of Action Explained.

Why Is Colistin So Hard to Find? 3 Key Reasons

1. Very Few Manufacturers

Unlike common antibiotics that are made by dozens of generic drug companies, Colistimethate Sodium is produced by only a handful of manufacturers worldwide. Xellia Pharmaceuticals (based in Denmark) and Par Pharmaceutical (now part of Endo International) are among the primary suppliers for the U.S. market. When even one manufacturer experiences a production delay, the entire national supply can be disrupted.

The manufacturing process for Colistin is complex — it relies on fermentation-based production, which is more unpredictable and time-consuming than chemical synthesis. This limits how quickly production can ramp up when demand spikes.

2. Surging Demand From Drug-Resistant Infections

Multidrug-resistant (MDR) gram-negative infections are on the rise globally. The CDC and WHO have both flagged carbapenem-resistant organisms as urgent threats, and Colistin is often the only antibiotic that still works against them. As resistance rates climb, hospitals are ordering more Colistin than ever before — but the supply hasn't kept pace.

This isn't just a U.S. problem. Hospitals around the world are competing for the same limited supply, which pushes availability even lower domestically.

3. Ongoing Supply Chain Disruptions

Colistimethate Sodium has appeared on the ASHP (American Society of Health-System Pharmacists) drug shortage list repeatedly. Supply chain issues — from raw material sourcing to shipping delays — have made shortages worse. Because the active pharmaceutical ingredient (API) is sourced from specialized producers, any disruption at the API level ripples through the entire supply chain.

Additionally, because Colistin is a hospital-use injectable rather than a retail pharmacy pill, patients can't simply shop around at their local CVS or Walgreens. The supply chain for hospital injectables is fundamentally different and more fragile.

4. Low Profitability Discourages New Entrants

Colistin is an old, off-patent drug. The price per vial — typically $31 to $44 at wholesale — doesn't offer the profit margins that attract new generic manufacturers. When the cost of setting up fermentation-based production exceeds the potential revenue, companies simply don't enter the market. This keeps the supplier pool small and the shortage risk high.

What You Can Do

Finding Colistin takes persistence, but there are real steps you can take:

• Use Medfinder: Medfinder helps you search for medications in stock at pharmacies near you, including hard-to-find injectables like Colistin.
• Talk to your infectious disease specialist: Your doctor may be able to source Colistin through hospital pharmacy networks or specialty distributors that aren't available to the general public.
• Ask about alternatives: If Colistin is truly unavailable, your provider may consider alternatives like Polymyxin B, Tobramycin, or Amikacin depending on your infection.
• Contact the hospital pharmacy directly: Since Colistin is primarily used in inpatient settings, hospital pharmacies may have stock or be able to order it through specialty channels.
• Check shortage updates: Stay informed about the latest Colistin availability through our shortage update for patients.

Final Thoughts

Colistin is a critical, life-saving antibiotic — and the fact that it's so hard to find is a serious problem. The combination of limited manufacturers, rising demand from drug-resistant infections, and fragile supply chains has created a perfect storm of scarcity.

If you or a loved one needs Colistin, don't give up. Use every tool available — from Medfinder to your healthcare team — to track down this medication. And if you're concerned about cost, check out our guide on how to save money on Colistin.

The shortage won't last forever, but right now, being proactive is your best strategy.