If price competition makes your head ache, stay away from San Antonio, where top retail chains are waging a bruising battle over analgesic sales. Nationwide, Tylenol dominates this $2.62 billion category with a full one-third of retail sales across the food, drug and mass channels. Locally, Excedrin manages a 5.2% share for fourth rank. As for that old standby, plain aspirin, it's barely in the picture -- top-selling Bayer manages just a 4.4% share for a No. 5 rank locally.
