Patients are demanding doctors' orders for over-the-counter products because of a provision in the healthcare overhaul that slipped past nearly everyone's radar. It says people who want a tax break to buy such items with flexible-spending accounts need to get a prescription first. The result is that Americans are visiting their doctors before making a trip to the drugstore, hoping their physician will help them out by writing the prescription. The new requirements create not only an added burden for doctors, but also new complications for retailers and pharmacies. Though the new rules on over-the-counter drugs amount to a small part of the massive overhaul of the health-care system, the unintended side effects show how difficult it can be to predict how such game-changing legislation will play out in the real world. Some doctors, irked by the paperwork and worried about lawsuits, are balking at writing the new prescriptions. Pharmacists and retailers say the changes mean they have to apply a personalized label on some 15,000 different everyday products for customers paying with certain debit cards.