Facebook API input sanitization

For all those of you using the Facebook API for PHP: I just ran into an issue concerning Facebook User IDs/Facebook Page IDs when trying to sanitize get variables passed amongst different php files. As usual, I used intval() to avoid SQL Injections, but intval() will kill all values above a certain limit - and some Facebook IDs are above. Any ideas for a workaround here?

 

http://php.net/manual/en/function.mysql-real-escape-string.php
or just simply

$x = (int) $x;

PHP: