Cephalon Inc Logo Cephalon Inc.’s Fentora (fentanyl buccal tablet) has been approved by the U.S. Food and Drug Administration to treat so-called “breakthrough” pain in those who have cancer. This type of pain -characterized by its rapid onset, intensity and short duration — affects about 800,000 cancer patients, the American Cancer Society says.

Fentora, an oral opioid, is partially absorbed through the cheek into the bloodstream, making it faster-acting than similar drugs absorbed through the gastrointestinal tract, Cephalon said in a statement.

The drug was approved for people who are already tolerant of opioid therapy for persistent cancer pain. Side effects of opioids may include decreased respiration and circulation, nausea, and fatigue.

Cephalon said it expects Fentora to be available in the United States during the first week of October.