A batch of cancer medication has been recalled over microbial contamination after medics noticed the tablets were discoloured. Mercaptopurine is a type of chemotherapy drug used to treat some types of leukaemia. The tablets should be pale yellow.

A notice issued by the Medicines and Healthcare products Regulatory Agency (MHRA) said: “Aspen Pharma Trading Limited is recalling a specific batch of Mercaptopurine 50mg tablets as a precautionary measure due to microbial contamination following a small number of complaints of discoloured tablets within the packs, identified when the packs have been opened by healthcare professionals.The contamination has been identified as Penicillium Kongii.”

The affected batch of 50mg tablets has the code P0010384. It was first distributed in January and has an expiry date of December 31, 2028.

Patients and carers were urged to check the batch number on the label of the medicine bottle.

The MHRA notice added: “The tablets should be a ‘pale yellow colour and are marked with ‘PT / 50’, as per the Patient Information Leaflet (PIL).

“If you have tablets that are discoloured in any way, from the affected batch please contact your relevant healthcare professional responsible for your treatment, e.g. specialist or prescriber.

“Patients should not stop taking their medication without discussing this with their specialist or prescriber as there may be a need for additional monitoring.”

Mercaptopurine works by stopping cancer cells making and repairing DNA.

It can be taken with food or on an empty stomach, but should not be taken with liquid milk or dairy products such as yoghurt and cheese.