Drug developers working on harder-to-abuse pain remedies, including Pain Therapeutics (Nasdaq: PTIE), King Pharmaceuticals (NYSE: KG), and Alpharma (NYSE: ALO), got a guarded thumbs-up from the FDA last week.

Last Thursday, the FDA released an advisory panel briefing document (a report that summarizes some of the agency's views on a particular drug or issue) in preparation for today's hearing on marketing approval for a new harder-to-crush-and-dissolve version of Purdue Pharma's OxyContin. The document and today's hearing will let the agency air its worries about the entire class of abuse-resistant opioid pain drugs.

Based on the just-released document, the FDA doesn't appear to have any major problems with this new class of therapies. And while the FDA did have specific objections to Purdue Pharma's own abuse-resistant OxyContin that could delay its approval, the agency's qualms don't necessarily extend to similar therapies from competitors.

Purdue plans to remove all the easier-to-abuse versions of OxyContin from the market if the equivalent abuse-resistant versions are approved. However, the FDA seems concerned that Purdue hasn't yet finished testing an abuse-resistant version of the highest 80 mg dosage; a regular version at this dosage would remain available, even if the improved lower doses were approved.

Purdue does plan to file a marketing application for the 80 mg dosage, but in its briefing document, the FDA's Controlled Substance Staff and Division of Risk Management expressed concerns about the "unintended consequences" of selling multiple versions of the product simultaneously. However the advisory panel votes today, I predict that the FDA will delay abuse-resistant OxyContin until Purdue can get all its dosages ready for approval.

These advisory panel briefing documents don't address some of the individual risks that Purdue's most immediate competitors, like Durect (Nasdaq: DRRX) and Pain Therapeutics, may face. Overall, though, the FDA seemed open to the prospects of harder-to-abuse opioid pain drugs.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. The Fool has an A+ disclosure policy.