Af teoretiske grunde bør det derfor undgås til patienter med sjældne arvelig mangel 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 phosphoribosyl-transferase (HGPRT) such as Lesch-Nyhan and Kelley- Seegmiller syndrome.