Abstral (generic: fentanyl) is a prescription medication used to treat breakthrough pain in adults with cancer who are already taking other opioid pain medicines around-the-clock for cancer pain. Abstral belongs to a group of drugs called opioids that work by binding to opioid receptors within the central nervous system to relieve pain.

This medication comes in tablet form to be taken underneath the tongue (sublingual) where it is dissolved. Do not eat or drink anything until the tablet dissolves.

Common side effects of Abstral include constipation, nausea, sleepiness, and headache. Do not drive or operate heavy machinery until you know how Abstral affects you.