Af teoretiske grunde bør det derfor undgås til patienter med sjælden arvelig på hypoxantin- guanin- fosforibosyltransferase (HGPRT) såsom Lesch- Nyhan og Kelley- Seegmiller syndrom.
On theoretical grounds, therefore, it should be avoided in patients with rare hereditary deficiency of hypoxanthine-guanine phosphoribosyltransferase (HGPRT) such as Lesch-Nyhan and Kelley-Seegmiller syndrome.