Uses
Fentanyl falls under the category of narcotic analgesics, this means basically that it is a pain reliever that relieves pain without the patient losing consciousness. Another narcotic analgesics include morphine and oxycontin. Fentanyl is used in two major ways: by taking orally or by using a patch.
Orally:
When fentanyl is taken orally its call an oral transmucosal fentanyl citrate, it is taken as a "lollipop". When it is placed in the mouth a reaction occurs between saliva and the fentanyl. This reaction occurs because fentanyl is lipid soluble opiod. This basically means that when the fentanyl is placed in saliva it reacts with the lipids and a solution is produced. Of this solution about 25% is absorbed in the mucous glands in the mouth which take it to the blood stream providing the first effects of pain relief within 3 to 5 minutes of putting the "lollipop" in your mouth. The highest effects of the pain relief will come after about 30 minutes. This is mostly used by cancer patients who suffer from breakthrough cancer pains. This basically means that the pain relievers that they take on a regular basis for the lasting pain do not always completely take the pain away and some pain still comes. The oral fentanyl is a solution to the problem because it can relieve the pain so quickly and easily.
Patch:
The fentanyl patch is also an effective way to relieve ongoing pain of cancer patients as well as for those after a surgery or injury. The patch is also very useful in the veterinary field because since the patch, unlike the oral form of fentanyl, is used on an ongoing basis it good for animals. This is because an animal is unable to display pain to humans. The patch is worn for a period of approximately 72 hours.

Illegal Use:
Fentanyl is used illegally for a feeling of intense happiness that is provided by narcotics such as fentanyl. However this feeling is often followed by some of the negative side effects listed below. Another reason that fentanyl is bad to use illegally is because it is highly addictive. Since it is taken most often using a shot, when used illegally some of the transmitted diseases such as AIDS and hepatitis can be transmitted as well.
Side Effects:
Dizziness
Light headedness
Shortness of Breath
Anxiety
Hearing/ Feeling things that are not there
Overdose Effects: