[2] According to its current French package insert, cicletanine is officially in the category of “Other cortical segment diuretics.” (French: “Autres diurétiques du segment cortical de dilution.”) Internationally, cicletanine’s ATC Code C03BX03 is a subcategory under C03BX “Other low-ceiling diuretics.” This categorization as a diuretic (without mention of other activity) is despite (1) very early indications that the drug had therapeutic activity beyond diuresis (in some cases at sub-diuretic doses) and (2) subsequent findings on multiple mechanisms of vasorelaxation.

In fact, the Nobel Prize in Physiology or Medicine was given the prior year to Sune Bergström, Bengt Samuelsson and John Vane for work on prostaglandins, including prostacyclin, which Vane had demonstrated to be a vasodilator and inhibitor of platelet aggregation.

Cicletanine's official categorization as a diuretic notwithstanding, the drug's antihypertensive activity as experienced in most patients involves relaxation of arteries more than decrease of vascular-fluid volume (i.e., via diuresis).

While a comprehensive survey of cicletanine's mechanism of action has yet to be published, it is now known that the drug's vasorelaxant activity is due to (1) reversal of endothelial dysfunction via activation of eNOS (endothelial nitric oxide synthase), and (2) increase of prostacyclin.

In research conducted at the US NIH, cicletanine has been demonstrated as an inhibitor of protein kinase C and marinobufagenin.