Welcome to http://www.online Chem-Junction.Abstral is a rapidly disintegrating sublingual (under the tongue) tablet containing fentanyl. The product is approved for the treatment of breakthrough cancer pain in patients already treated with opioids, such as morphine, for underlying chronic cancer pain.Abstral (fentanyl sublingual) is an opioid pain medication. An opioid is sometimes called a narcotic. Fentanyl sublingual is placed under the tongue.Abstral is used to treat “breakthrough” cance