Philadelphia ? Drug companies that make generic knockoffs of brand-name medications may also, under some circumstances, copy the way pills look, a federal appeals court ruled.

The 3rd U.S. Circuit Court of Appeals ruled Friday that a company that makes a generic equivalent of the hyperactivity drug Adderall may use the same color scheme to identify its pills as Adderall’s manufacturer, Shire U.S. Inc.

Since 1996, Adderall tablets with smaller doses have come in blue, while larger doses are light orange.

Barr Laboratories uses the same two colors to distinguish between small and large doses of its generic version of the drug, which began selling in 1998.

Shire filed suit last year and asked a federal judge for an injunction to force Barr to change the way its pills looked.

In its ruling Friday, the 3rd Circuit upheld a lower-court’s decision denying the injunction. It said making the pills look similar had an important benefit for the drug’s primary users: people with Attention Deficit Hyperactivity Disorder.

Under U.S. regulations, pharmaceutical companies are allowed to make generic versions of popular drugs whose patents have expired.

Shire had argued that while Adderall and the Barr generic were both made with amphetamine salts, and ostensibly have the same therapeutic effect, some of the components are different. Tablets made by Barr, for example, contained saccharin, while Adderall did not.

Barr spokeswoman, Carol Cox, praised the ruling.

“Actually, our blue was a shade off from theirs, and it was completely within the realm of what the FDA allows,” she said.

A message left at Shire’s media relations office was not immediately returned.

The ruling doesn’t completely resolve the case but indicates Shire is unlikely to prevail if it goes to trial. It also doesn’t affect a separate legal dispute between the two companies over a patent issued for Shire’s new version of the drug, Adderall XR.