Israeli-based Teva Pharmaceuticals, the world’s largest generic drug company, has begun shipping its generic version of the stimulant medication Adderall XR for the treatment of ADHD, known as Attention Deficit Hyperactivity Disorder.

Adderall XR, the beaded, extended-release form of the medication, is a combination of four different dextroamphetamine salts that release into the blood system at varying lengths of time, thus allowing for "coverage" throughout a target 8-to-12 hour period. Adderall tablets (non-XR) have been available in generic form for years. The stimulant class is considered a first-line medication in the treatment of ADHD.

The marketing of the drug follows Teva’s acquisition of Barr Pharmaceuticals, which previously won the exclusive right to sell a generic version of the Adderall XR capsules for six months after beginning commercial shipments.

Barr had agreed to delay shipments until this month in return for the Ireland-based Shire company, which produced Adderall, to drop its patent suit.

Sales of Adderall XR were approximately $1.5 billion in the 12-month period ending February 28, and Teva is hoping the generic version will give it a firm footing in the growing market for ADHD, also known as ADD (Attention Deficit Disorder).

Drugs such as Adderall and Ritalin (methylphenidate) have been highly controversial due to charges of their being over-prescribed. There are also claims of older teens and college students for whom the medication has been prescribed sometimes sharing their pills with friends who want to stay awake to study for exams. Although stimulant medication does not have a "stimulating" effect on individuals with ADHD, it has been used by students and others to remain alert beyond their normal ability to do so. 

An NBC news report last week noted that drug manufacturers may develop up to 600 types of new drugs over the next several decades to help improve concentration, memory and learning.