New drugs are developed by pharmaceutical companies and are patented. That patent gives a company the right to sell the drug exclusively for the next seven to ten years. If it’s a good drug, the company stands to make billions of dollars.  When the patent runs out, the drug becomes “Generic”. It’s manufactured by many companies at a much reduced  price. In order to prevent a loss of revenue, the original company can make a slight molecular change on the drug and apply for a new patent. A “new” drug is therefore created which might be no better than the old one. However, it sells for ten times as much and  its new name is heavily advertised until the old name is forgotten. This is why the Old Timer takes generics whenever possible.