When it comes to one law, Pittsburg is an island. In Missouri, Joplin and Branson have adopted ordinances in recent years requiring those who purchase medicine with pseudoephedrine — a key ingredient in the manufacture of methamphetamine — to have a prescription. Pittsburg, the last city with a pharmacy in this area that does not have such a law on the books, has yet to formally consider an ordinance for restricted sale. But the time is coming.