The effect of some iodinated contrast media on human plasma butyrylcholinesterase activity

The effect of three iodinated contrast media (CM) on human plasma butyrylcholinesterase (BuChE) activity was studied during the intravenous pyelography (i.v.P). BuChE is an enzyme that participates in the metabolism of acetylcholine and hydrolyzes food esters and drugs such as nondepolarizing muscle relaxants and local anesthetics. The three CM were: diatrizoate (an ionic substance) and iohexol and iopentol (two nonionic substances). Five minutes after the intravenous injection, iohexol reduces BuChE plasma activity by 8.5% but this effect disappears within 15 minutes. Diatrizoate and iopentol decrease BuChE plasma activity by 8% and 15.2%, respectively, 5 minutes after the injection and this effect remains stable for the next 15 minutes. The underlying mechanism is unknown. Plasma BuChE activity remains within the normal range in any case and no association with side effects can be made. Thus, according to the above findings, it is not possible to connect or exclude any relationship between BuChE plasma activity and CM-derived adverse reactions during the i.v.P.