By Mariann Caprino
NEW YORK _ The race is on to sell drugs by mail.
A sleepy, back-office operation just a decade ago, the mail-order drug business suddenly is crowded with new players, each vying for a piece of a mushrooming $4 billion market.
It doesn't mean the postman is about to replace your neighborhood pharmacist, but it is changing the way millions of Americans on health plans get prescription medicines.
Seventy percent of all prescriptions are for so-called "maintenance drugs," taken regularly for chronic ailments like arthritis and high blood pressure.
It is this business mail-order pharmacies seek to …