This is interesting because I'm a nurse and I deal with people who occasionally test positive for methamphetamine.
We've found that many of these people take Zantac (aka ranitidine, used for acid reflux). This hasn't been studied since 1991[0] but it probably should be again, given increasing rates of meth use.
I wish the author had given the name of her prescription inhaler- Vick's Vapor inhaler has been shown to test positive but albuterol and other steroid inhalers are more common.