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Patients taking Promixin must be switched to an alternative by 30 April 2025, the Department of Health and Social Care (DHSC) and NHS England have said.
A national patient safety alert, issued on 17 March 2025, said that Promixin (Colistimethate; Zambon UK Limited) 1-million-unit powder for nebuliser solution unit dose vials (UDVs) will be discontinued from May 2025.
As a result, the alert said that no new patients are to be initiated onto Promixin. People already taking it must be identified, reviewed and referred to their respiratory specialist so that they can be supported to switch to a suitable alternative.
“Proactively identify and review all patients currently prescribed Promixin 1-million-unit powder for nebuliser solution UDVs and immediately refer them to their respiratory specialist to switch to an alternative colistimethate preparation,” the alert advised.
It added that this is a “safety critical and complex national patient safety alert”.
“Implementation should be co-ordinated by an executive lead… and supported by clinical leaders in pharmacy, community pharmacy, GP practices and clinical leaders in respiratory and cystic fibrosis,” the alert said.
The alert has also been issued to medical directors of NHS health boards and directors of pharmacy in Scotland.
Promixin is a formulation of the antibiotic colistimethate. It is licensed for chronic pulmonary infections owing to Pseudomonas aeruginosa in adults and children with cystic fibrosis, as well as non-Pseudomonas aeruginosa infection in patients with non-cystic fibrosis bronchiectasis or bronchial sepsis.
In the UK, there are around 11,000 people with cystic fibrosis, and Pseudomonas aeruginosa is a major cause of chronic lung infections in these patients.
The alert notes that Colicym (Colistimethate; Kent Pharma) 1-million-unit powder for nebuliser solution UDVs are still available, and providers should consider this instead. If Colicym is not suitable, the alert says that Colomycin 1-million or 2-million-unit powder for solution for injection, infusion or inhalation should be considered.
However, it adds that stocks of Colomycin are currently in short supply, and that Colomycin preparations “should be reserved for patients already maintained on this treatment or for those who require treatment via the intravenous route”.
It also says that patients switching products must be supported in how to use their nebulisers to get the correct dose.
Millie Harris, lead respiratory pharmacist at Worcestershire Acute Hospitals NHS Trust, said: “Locally, our Promixin prescribing is relatively low, as our preferred brand is Colomycin powder for solution for injection, infusion or inhalation vials.
“However, given the current intermittent supply disruption with Colomycin, the brand Colicym 1-million-unit powder for nebuliser solution has been recommended as an alternative to Promixin, which can support an increase in demand.
“To support with this switch, patients should be provided with education and training under specialist supervision on how to use the new nebuliser device to administer the correct dose.”
