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Colistimethate (marketed as Coly-Mycin M and generic products) - Full Version

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On June 28, 2007, the Food and Drug Administration issued a public health advisory titled: Colistimethate.

The drug is also known and marketed as Coly-Mycin M.

I am Pat Clarke from F-D-A's Center for Drug Evaluation and Research.

FDA issued this public health advisory in response to a report about the death of a patient with cystic fibrosis who used the antibiotic Colistimethate that had been pre-mixed by a pharmacy into a liquid for inhalation with a nebulizer.

A nebulizer is a device that turns liquid medicine into a mist which is breathed in by patients to deliver the medication directly to their lungs.

Nebulizers are commonly used by patients with cystic fibrosis. The Colistimethate that was used by this patient had been prepared and dispensed by the pharmacy as a ready-to-use liquid.

When Colistimethate is mixed into a liquid form, the product begins to break down into other chemicals that can damage lung tissue.

Colistimethate is used to treat infections caused by certain types of bacteria, including the bacteria pseudomonas aeruginosa (sue-duh-moan-us are gin oh sa), a germ that is known to cause serious lung infections in patients with cystic fibrosis.

In light of this reported patient death, FDA offers the following recommendations:

  • If patients use the liquid form of Colistimethate in a nebulizer, it should be used promptly after being mixed.
  • Patients should discard any unused pre-mixed liquid form of Colistimethate.
  • Healthcare professionals who use Colistimethate to treat patients with cystic fibrosis should be aware of the potential for serious and life-threatening side effects from inhalation of pre-mixed, ready-to-use liquid forms of Colistimethate. The side effects are as a result of local toxicity to the lung and airway. More details of these effects are provided in the information for healthcare professionals and in the full prescribing information for Colistimethate which can be found at:

    W-W-W dot F-D-A dot G-O-V backslash C-D-E-R backslash D-R-U-G backslash I-N-F-O-P-A-G-E backslash C-O-L-I-S-T-I-M-E-T-H-A-T-E backslash D-E-F-A-U-L-T dot H-T-M
  • Healthcare professionals who treat patients with cystic fibrosis should work out a treatment plan with their patients that best meets their needs.
  • Patients and/or caregivers with questions or concerns about this advisory should contact their healthcare provider or their cystic fibrosis care center to determine how best to continue treating their infection.


Colistimethate is FDA approved only for injection into a vein or a muscle; it is not FDA approved for use as a liquid to be inhaled via a nebulizer.

We urge both healthcare providers and patients to report side effects from medical products to the MedWatch program by phone at 1-800-F-D-A-ten-88 or by the Internet at F-D-A dot G-O-V slash M-E-D-W-A-T-C-H.



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