Drug enforcement officials increased the limit on US production of ADHD drugs Ritalin and Concerta, along with their generic versions, amid nationwide shortages of the medications.

The Drug Enforcement Administration allows manufacturing of 53.3 million grams this year of the active ingredient in the drugs, methylphenidate, according to a public notice filed Friday. The earlier limit had been 41.8 million grams, according to the notice.

“This adjustment is necessary to ensure that the United States has an adequate and uninterrupted supply of methylphenidate (for sale) to meet legitimate patient needs,” the notice said. The DEA declined to comment.

Made by a variety of manufacturers, generic ADHD treatments used by millions of Americans have been in short supply over the past year, beginning with Adderall in 2022, leaving many patients without needed treatment. The Food and Drug Administration requested Aug. 10 that the DEA increase the production limit in order to address shortfall, according to the notice.

Most ADHD medications are classified as controlled substances, meaning that the government sees them as addictive and subject to abuse. Companies have said that the production controls make it difficult to meet patient demand.