The U.S. Food and Drug Administration approved KemPharm Inc.'s new drug application for its painkiller Apadaz.

The agency has approved the drug for the short-term, no more than 14 days, management of acute pain severe enough to require an opioid drug and for which alternative treatments are not adequate.

Apadaz is a combination of the company's prodrug benzhydrocodone, which is chemically inert or inactive on its own, and acetaminophen.