# Methylthioninium chloride (Lumeblue, for colonoscopy)

Source: https://onco.cc/drugs/methylthioninium-chloride-lumeblue/  
OnCo record `methylthioninium-chloride-lumeblue` (Imaging agent). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Lumeblue is a blue dye taken as tablets the day before a colonoscopy. It stains the lining of the bowel so that the doctor can see polyps and early cancers more easily during screening or follow-up.

## Summary

Methylthioninium chloride (Lumeblue, previously Methylthioninium chloride Cosmo; marketing authorisation holder Cosmo Technologies Ltd) has been authorised in the EU since 19 August 2020 (CHMP opinion 25 June 2020) as a diagnostic agent enhancing visualisation of colorectal lesions in adults undergoing screening or surveillance colonoscopy. It is a hybrid medicine whose reference medicine is Metilénkék Pharmamagist, authorised in Hungary. The tablets are taken by mouth the day before the colonoscopy together with the bowel preparation. In the study the EMA summarises, at least one adenoma or carcinoma was found in 56 per cent of patients who took it (273 of 485) against 48 per cent of those who did not (229 of 479), confirmed on the removed tissue, without more false positives. The commonest side effect is discoloured urine and faeces, which clears after a few days.

## Fields

- Kind: Imaging agent
- Status: approved
- Last checked: 2026-11-03
- Also known as: methylthioninium chloride; methylene blue; Lumeblue; Methylthioninium chloride Cosmo
- Tags: universe-gap; ema-register; diagnostic
- Brand: Lumeblue
- Modality: Oral contrast agent for colonoscopy (blue dye, delayed-release tablet)
- Mechanism: Methylthioninium chloride (methylene blue) enters the cells lining the bowel and stains them for a while. Different kinds of cell take up different amounts, so abnormal areas stand out; the tablet coating lets the dye reach the colon before it is slowly released (EPAR overview, EMA).
- Approvals: EU 2020: Diagnostic agent enhancing visualisation of colorectal lesions in adults undergoing screening or surveillance colonoscopy

## Sources

- EMA: Lumeblue (EPAR): https://www.ema.europa.eu/en/medicines/human/EPAR/lumeblue

## Connected records

- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/)
- terms: [Adenoma detection rate](https://onco.cc/terms/adenoma-detection-rate/), [Colonoscopy](https://onco.cc/terms/colonoscopy/), [Polyp types in the bowel](https://onco.cc/terms/colorectal-polyp-types/)

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