load-{$pagenow}

Fires before a particular screen is loaded. The load- hook fires in a number of contexts. This hook is for core screens. The dynamic portion of the hook name, `$pagenow`, is a global variable referring to the filename of the current screen, such as 'admin.php', 'post-new.php' etc. A complete hook for the latter would be 'load-post-new.php'.