The drug, lisdexamfetamine dimesylate, has a slow-release action that activates the amphetamine ingredient over the course of a day, helping levels of alertness and concentration in children with ADHD (attention deficit hyperactivity disorder).

It was assessed under the European Union's decentralized approvals procedure, led by Britain's medicines watchdog. The application was supported by two European studies and clinical data from the United States.

Seven other EU countries - Denmark, Finland, Germany, Ireland, Norway, Spain and Sweden - participated, and they have agreed product labels. They will now issue their own national approvals, a process that takes up to three months, Shire said.

Chief executive Angus Russell said: "As all ADHD patients are different and will vary in their responses to the available treatments, we believe introducing Elvanse will provide physicians with a broader range of options to help patients with ADHD manage their individual needs effectively".

Shire has established a leading position in treating hyperactivity in the United States with its stimulants Adderall XR and Vyvanse. The latter saw sales rise 24 percent to $247 million in the three months to September.

Shore Capital analyst Brian White said while he had modest sales expectations in the short term for the drug in Europe, where it will be the first amphetamine to be approved for ADHD, the decision was significant because the condition was becoming better known in Europe.

"Shire has been very successful in the U.S. with its ADHD franchise and one would expect them to use that experience to do a similar job in Europe, although that will take a lot longer just given the much lower awareness," he said.

"They have another product coming along later (Intuniv) which is a non-stimulant, and that could be more appropriate for the European market than a stimulant."

Vyvanse, which Shire said was the top-selling branded prescribed ADHD medicine in the United States, has been indicated in Europe for ADHD in children aged six years and over when treatment with methylphenidate, better known as Ritalin, was not successful.

(Editing by Dan Lalor)

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