The case involves a practice called product hopping where brand name manufacturers make a slight alteration to their prescription drug (PDF) and engage in marketing efforts to shift consumers from the old version to the new to insulate the drug company from generic competition for several years. For its part Actavis argued that an injunction would be "unprecedented and extraordinary" and would cause the company "great financial harm, including unnecessary manufacturing and marketing costs." Namenda has been a big seller. In the last fiscal year, the drug generated $1.5 billion in sales. The drug costs about $300 a month.