Why does norco cause constipation?

http://wiki.answers.com/norco/norco.html® (http://wiki.answers.com/hydrocodone-apap/hydrocodone-apap.html) is a prescription pain medication. Because it contains a narcotic, Norco is likely to cause constipation. Although you may avoid this side effect if you take Norco for just a few days (or if you only take it occasionally), the majority of people who take the drug will develop some degree of constipation.