Medicine shortage: Promixin to be discontinued from May 2025

The Department of Health and Social Care (DHSC) and NHS England have issued a national patient safety alert regarding the upcoming shortage of Promixin (colistimethate).

The alert, issued on 17 March 2025, states that Promixin (colistimethate) 1-million-unit powder for nebuliser solution unit dose vials (UDVs) will be discontinued from early May 2025, with stocks expected to be exhausted by this time.

As a result, primary and secondary care providers are advised not to initiate new patients on Promixin and to switch patients on this drug to an alternative colistimethate preparation by 30 April 2025.

“Pro-actively identify and review all patients currently prescribed Promixin 1million unit powder for nebuliser solution UDVs and immediately refer them to their respiratory specialist to switch to an alternative colistimethate preparation,” the alert said.

Reason for supply shortage

Promixin is licensed for treating chronic pulmonary infections caused by Pseudomonas aeruginosa in adults and children with cystic fibrosis.

It may also be prescribed for the treatment of Pseudomonas aeruginosa colonisation and infection in adult and paediatric patients with non-cystic fibrosis bronchiectasis or bronchial sepsis.

According to the alert, the shortage is due to the “discontinuation of I-neb devices, discs, and consumables from an external manufacturer,” making it no longer viable to produce further supplies of Promixin.

Respiratory specialists in secondary care are advised to consider the patient’s diagnosis and prescribe either:

• Colicym (1-million-unit powder for nebuliser solution unit dose vials)
• Colomycin (1-million- or 2-million-unit powder for injection, infusion, or inhalation), if Colicym is unsuitable

However, it notes that the supply of Colomycin is currently limited, and current stock should be reserved for “patients already maintained on this treatment or for those who require treatment via the intravenous route.”

In contrast, Colicym vials are available and can support an increase in demand, the alert said.

Clinical leaders across pharmacy, community pharmacy, GP practices, and respiratory and cystic fibrosis care are asked to support the transition of patients to alternative treatments.

The alert adds that when switching colistimethate products, patients should be provided with appropriate education and training to ensure they can use the new nebuliser device and administer the correct dose.