Aug 31 (Reuters) - Drugmakers have begun shipping copycat versions of Takeda Pharmaceutical's drug Vyvanse, which is expected to offset the ongoing shortage of the ADHD medicine in the United States.

The U.S. Food and Drug Administration had said on Monday it has approved generic versions of Vyvanse from 11 drugmakers after Takeda's exclusivity over the drug expired on Aug. 24. Copycats of the drug come in capsules and chewable tablets, ranging between 10 milligrams to 70 milligram doses.

U.S.-based drugmakers Mallinckrodt and Viatris , UK-based Hikma Pharmaceuticals and Indian drugmaker Sun Pharmaceutical Industries confirmed on Thursday they began shipping their generic versions of the drug, which is also approved for a binge-eating disorder in adults.

The generic drugmakers said they are working with the Drug Enforcement Administration (DEA) as the drugs are classified as a controlled substance.

Controlled substances are medications that can cause physical and mental dependence, and have restrictions on how the prescriptions can be refilled.

"We will be working closely with the DEA to request and secure additional quota to increase our production following this approval," Mallinckrodt said.

Since October, the FDA has warned of an ongoing shortage of Teva Pharmaceutical Industries Ltd's Adderall, after the Israel-based drugmaker had flagged intermittent manufacturing delays.

That shortage led to a jump in demand for Vyvanse, which combined with manufacturing issues, has resulted in a shortage of Takeda's drug.

(Reporting by Sriparna Roy in Bengaluru; Editing by Krishna Chandra Eluri)