New York’s attorney general has filed an antitrust lawsuit that accuses Forest Laboratories of steering patients toward a newer version of its Alzheimer’s medication Namenda (memantine). The New York Times reports that the lawsuit concerns the drugmaker’s decision to stop producing the tablet form of the drug, a situation which would force patients to switch to the newer, extended-release Namenda XR capsules because the older, branded tablet version would not be an option. The suit also claims it was still too early in the patent life cycle for generics to enter the marketplace, leaving patients with only one choice.

The Times explains that the strategy of modifying a drug just enough to make it different from its predecessor is called product-hopping, and is one that drug manufacturers use to “try to sidestep generic competition.” In this case, the changefrom tablet to capsule form—is one that New York AG Eric Schneiderman alleges in this case to be an attempt “to maintain its monopoly even after its patent expires,” writes the paper.

Forest parent company Actavis would not talk with the Times, but the Grey Lady notes that product-hopping’s history includes cases such as one brought against AstraZeneca when it introduced the gastric reflux medication Nexium (esomeprazole magnesium), which critics called a variation of its existing heartburn medication Prilosec (omeprazole). Unlike Forest, AstraZeneca did not stop making Prilosec.

A court dismissed the AstraZeneca case, but the Times notes that a court did not dismiss a case against Abbott Laboratories over its decision to remove older versions of its cholesterol drug TriCor (fenofibrate) when a new one came out, and before generics hit the market.

The Times notes that there is currently a Namenda XR shortage and that the older tablets will be available, even after Forest’s own August 15 deadline to stop making them.