Codeine

Like morphine, codeine is an alkaloid (a naturally occurring base) of opium, a drug made from the milky juice of unripe seed capsules of the opium poppy plant. The opium poppy was once native to Asia Minor (a large penninsula in western Asia between the Black Sea and the Mediterranean), but it is now grown legally and illegally in many parts of the world. Codeine, morphine, opium, heroin, and other opium alkaloids—the opioids—make up the class of drugs known as the narcotic analgesics. Because of their ability to relieve pain, narcotic analgesics have been some of the most important drugs in medicine.

An Ancient Pain Reliever

Opium is believed to have been used by the people of Babylonia (an ancient empire in southwest Asia) in 4000 B.C. as a pain reliever and to promote sleep. The first undisputed (certain) writings about poppy juice were by Greek philosopher Theophrastus in the third century B.C. Highly praised by peoples of many civilizations since that time, opium preparations were given the name laudanum (from the Latin word "laudare," meaning "to praise") by the Swiss physician Paracelsus (1493-1541). Beginning in the late 1600s until the discovery of anesthesia in the mid-1800s, a preparation of alcohol and opium, usually given in whisky or rum, was the drug most widely used to prepare patients for surgery.

Although opioids may be physiologically addicting in high doses, they are widely used. The use of heroin, however, is prohibited in the United States today, even in medicine. The abuse of opioids became worse with the introduction of the hypodermic syringe (needle), which made it easier to use opioids more frequently and in greater amounts. In early times, opium was usually smoked or eaten.

Today only a few opioids—mainly codeine, morphine, and papaverine—are useful in medicine. Codeine is the least habit-forming of the opioids. It is used to reduce pain and suppress (lessen) coughing. The amount of codeine that is naturally present in opium is small in relation to the amount of morphine found in opium, but codeine can be synthesized by a chemical change in morphine called methylation. Morphine is the most powerful painkiller available, and papaverine is used as a smooth muscle relaxant.

In the nineteenth century scientists began to separate the active ingredients of opium. This resulted in the isolation (separation) of morphine, codeine, heroin, and other opium alkaloids. When German pharmacist Friedrich Wilhelm Seturner isolated morphine from opium in 1805, a new era in drug production and use began. Soon many other new drugs were obtained by isolating active elements from crude drugs. One of these was codeine, which was discovered and named by Pierre-Jean Robiquet (1780-1840) in 1832. The chemical works of E. Merck, established in 1827 to manufacture morphine, began producing codeine the same year the drug was discovered. Years later, Thomas Anderson (1819-1874), a professor of chemistry at the University of Glasgow, Scotland, described the elemental makeup of codeine.

Cocaine Use Today

Today, codeine is commonly used in prescription drugs in combination with aspirin or acetaminophen to relieve pain, which it does by altering the way the brain reacts to painful sensations. It is also a common ingredient in prescription cough medicines. Codeine depresses the cough reflex by acting on a cough center in the part of the brain known as the medulla. It can be addictive, which is why it is only available by prescription. Many cough suppressants that do not contain codeine are available without a prescription. Codeine and other opioids cause nausea and vomiting in some patients.

Opium, morphine, and codeine are among drugs classified as Schedule II in the U.S. Comprehensive Drug Abuse Prevention and Control Act of 1970. This means they have a high potential for abuse and a severe like-lihood of causing physical or psychological dependence. Because of this, the federal government regulates how they are produced and how they are dispensed by pharmacists. It is illegal to make, sell, or use these drugs in any way that does not follow these governmental rules.

In the 1970s scientists discovered naturally occurring opioids in the brai called enkephalins. Many scientists believe a person becomes addicted to opioids because of a deficiency in these natural substances.