Antihistamines, which you might think would be a good choice for nasal symptoms, can unfortunately affect the bladder.
phenylephrine’s effectiveness as a nasal decongestant ... the federal government imposed new restrictions on purchasing pseudoephedrine, an ingredient that can be used in labs to make meth.
It was added to cold and flu remedies in the 1990s when another ingredient went behind the counter over illicit meth lab ...