Cadazolid is an experimental antibiotic of the oxazolidinone class made by Actelion Pharmaceuticals Ltd. which is effective against Clostridioides difficile, a major cause of drug resistant diarrhea in the elderly.

[2] Cadazolid progressed through to Phase III clinical trials,[1] but in its financial results for Q1 2018, Idorsia mentions that Actelion informed them that "following completion of Phase 3 data analysis of cadazolid - it has decided to discontinue the development of the compound.

"[3] The chemical structure of cadazolid combines the pharmacophores of oxazolidinone and fluoroquinolone antibiotics.

[2] In a study published in the journal Anaerobe, cadazolid has been shown to be effective in vitro against 133 strains of Clostridioides difficile all collected from Sweden.

[4] In phase I tests, sixty four male patients reacted favourably to cadazolid which primarily acted and remained in the colon while displaying little toxicity even in regimes involving large doses.