Pharmacological properties of cerium compounds.

Cerium is a member of the lanthanide series or rare earth elements which exert diverse biological effects mainly by their resemblance to calcium. This similarity, which is particularly characteristic for the lighter members of the lanthanide series, enables these elements to replace calcium in biomolecules without necessarily substituting for it functionally. While the inhibitory effects on calcium-dependent physiological processes (such as those involved in the blood clotting cascade as well as in neuronal and muscular functions) are well-known, their relevance for the pharmacological properties of cerium are less clear. Historically, cerium oxalate was used as an antiemetic, especially in vomiting of pregnancy and kinetoses, although its mechanism of action has never been clarified. At present, cerium nitrate is available as an adjunct to silver sulfadiazine cream for the topical treatment of extensive burns not amenable to early wound excision. Apart from direct antiseptic effects, cerium helps to prevent postburn sepsis and systemic inflammatory response by fixing burn toxins. The antineoplastic potential of cerium compounds, which had fallen into oblivion, is currently being re-explored in experimental settings, though the mechanistic basis remains to be elucidated.