678211 0
The prescription medicine OxyContin is displayed August 21, 2001 at a Walgreens drugstore in Brookline, MA. - 

Patent protection for the painkiller OxyContin expires today. That means generic drug manufacturers hope to soon grab a chunk of the nearly $3 billion market. But first, the FDA must give its blessing -- but right now, that's far from certain.

OxyContin is one of the most dangerous and widely abused drugs available. And the FDA is hesitant is to flood the market with a painkiller that's easily abused. So no matter how anxious generic drug makers are, RBC Capital Markets analyst Shibani Malhotra says the firms may have to wait.

"Every single company executive that we've spoken to believes that the market is going to have to move to tamper resistant products," Malhotra says. 

The FDA may require tamper-resistant drugs, like a pill that's impossible to crush into powder.

But Justin Collishaw, with Frost & Sullivan, says requiring tamper-resistant safeguards makes it harder for generics to get into the game. 

"Do I think that a generic manufacturer would develop their own tamper resistant formulation? The margins are not there," Collishaw says.

Industry observers believe the issue is so thorny, the FDA may remain silent over the coming weeks.  

Follow Dan Gorenstein at @dmgorenstein