Irukandji syndrome - Wikipedia, the free encyclopedia ally chosen. Pethidine (meperidine, brand name Demerol in the US) should be avoided, as large doses are often required for pain relief and in this situation significant adverse effects from the pethidine metabolite norpethidine may occur.[18] Magnesium sulfate has been proposed as a treatment for Irukandji syndrome after being apparently successfully used in one case.[19] Early evidence suggested a benefit;[20] however, according to a later report, a series of three patients failed to show any improvement with magnesium; the author reiterated the experimental status of this treatment.[21] Some preliminary laboratory experiments using the venom extracted from Malo maxima (the 'Broome Irukandji') on rat cardiovascular tissue in vitro has suggested that magnes with terminal_orbit