Morphine and fentanyl are both opioid analgesic drugs, meaning that they relieve pain by binding to structures called opioid receptors in the cells of the nervous system. Morphine is a naturally occurring opioid substance, or opiate, derived from opium poppy plants, or Papaver somniferum, while fentanyl is synthetic. Fentanyl is much more potent than morphine, and while some of their medical uses overlap, each has its own distinct applications.
Morphine (C17H19NO3) is a natural alkaloid found in the latex, a type of fluid produced in many plant species to deter herbivores, of opium poppy seeds. The latex that is extracted quickly dries up, resulting in a residue called opium. Morphine can then be extracted from it. Along with morphine, opium is also the source of another natural opiate, codeine, and a substance called thebaine that is used in the production of many semi-synthetic opioids such as oxycodone.
Fentanyl (C22H28N2O) does not occur in nature and was first synthesized in 1959. Its production begins with a chemical reaction between 4-Piperidinone (C5H9NO) and 2-Phenylethylbromide (C8H9Br) to produce the intermediate chemical N-Phenethyl-4-piperidinone (C13H17NO). This intermediate chemical then undergoes reactions with aniline (C6H5NH2), and sodium borohydride (NaBH4). The product of that reaction then reacts with propanoic anhydride ((CH3CH2CO)2O) to produce fentanyl.
Both morphine and fentanyl are used to relieve pain in trauma and surgical patients and for severe ongoing pain from injuries or from chronic illnesses such as cancer. Both drugs are also used to supplement anesthetics. Morphine can also be used for some medical purposes beyond analgesia and anesthesia, such as treating severe diarrhea and some respiratory conditions.
Fentanyl has much stronger effects than morphine. A given amount of fentanyl has about 100 times the potency of the same amount of morphine. Doses of morphine are usually measured in milligrams or tens of milligrams, while the same quantity of fentanyl would cause a lethal overdose if taken all at once. Fentanyl causes pain relief much more quickly than morphine, but its effects do not last as long. Consequently, morphine and fentanyl play different roles in pain management.
Morphine is used for ongoing pain relief in patients suffering chronic pain, while fentanyl is often reserved for so-called breakthrough pain. Breakthrough pain is a sudden, temporary increases in pain that does not respond to the patient's usual pain treatment. This often happens in people with ongoing pain caused by cancer. Fentanyl is also used for chronic pain patients who have developed a tolerance to less potent drugs such as morphine or who cannot take them due to their adverse effects.
Morphine and fentanyl can be taken in several ways. When used for surgical patients or trauma victims, they are often administered through injections. Both drugs can also be taken orally. Fentanyl taken for chronic pain management is often taken by means intended to administer the drug gradually, such as a lozenge or lollipop dissolved in the patient's mouth or a transdermal patch that slowly releases the drug into the skin. When used illegally as a recreational drug, morphine is sometimes inhaled or smoked.