Opium Drug, Physiological Actions & History, narcotic┬аdrug┬аthat is obtained from the unripe seedpods of the┬аopium poppy┬а(Papaver somniferum), a plant of the family┬аPapaveraceae. (See┬аpoppy.) Opium is obtained by slightly incising the seed capsules of the poppy after the plantтАЩs flower petals have fallen. The slit seedpods exude a milky┬аlatex┬аthat coagulates and changes colour, turning into a gumlike brown mass upon exposure to air. This raw opium may be ground into a powder, sold as lumps, cakes, or bricks, or treated further to obtain derivatives such as┬аmorphine,┬аcodeine, and┬аheroin. Opium and the drugs obtained from it are called opiates.
Opium┬аalkaloids
The pharmacologically active principles of opium reside in its┬аalkaloids, the most important of which,┬аmorphine,┬аconstitutes┬аabout 10 percent by weight of raw opium. Other active alkaloids such as papaverine and codeine are present in smaller proportions. Opium alkaloids are of two types, depending on chemical structure and action. Morphine, codeine, and thebaine, which represent one type, act upon the central┬аnervous system┬аand are┬аanalgesic, narcotic, and potentially┬аaddicting compounds. Papaverine, noscapine (formerly called narcotine), and most of the other opium alkaloids act only to relax involuntary (smooth) muscles.drug use: Opium, morphine, heroin, and related syntheticsThe opiates are unrivalled in their ability to relieve pain. Opium is the dried milky exudate obtained from the unripe seed pods of the…
Physiological actions of opiates
Opiates (e.g., morphine, codeine, and thebaine) exert their main effects on the┬аbrain┬аand┬аspinal cord. Their principal action is to relieve or suppress┬аpain. The drugs also┬аalleviate┬аanxiety; induce relaxation, drowsiness, and sedation; and may impart a state of euphoria or other┬аenhanced┬аmood. Opiates also have important physiological effects: they slow respiration and heartbeat, suppress the cough reflex, and relax the┬аsmooth muscles┬аof the┬аgastrointestinal tract. Opiates are addictive drugs; they produce a physical dependence and withdrawal symptoms that can only be┬аassuaged┬аby continued use of the drug. With chronic use, the body develops a tolerance to opiates, so that progressively larger doses are needed to achieve the same effect. The higher opiatesтАФheroin and morphineтАФare more addictive than opium or codeine. Opiates are classified as narcotics because they relieve pain, induce stupor and┬аsleep, and produce addiction. The habitual use of opium produces physical and mental deterioration and shortens life. An┬аacute┬аoverdose of opium causes respiratory depression which can be fatal.
Opium was for many centuries the principal painkiller known to┬аmedicine┬аand was used in various forms and under various names.┬аLaudanum, for example, was an alcoholic tincture (dilute solution) of opium that was used in European medical practice as an analgesic and sedative. Physicians relied on paregoric, a camphorated solution of opium, to treat┬аdiarrhea┬аby relaxing the gastrointestinal tract. The narcotic effects of opium are mainly attributable to morphine, which was first isolated about 1804. In 1898 it was discovered that treating morphine with acetic anhydride yields┬аheroin, which is four to eight times as potent as morphine in both its pain-killing properties and its addictive potential. The other alkaloids naturally present in opium are much weaker; codeine, for example, is only one-sixth as potent as morphine and is used mainly for cough relief. Since the late 1930s, various┬аsynthetic┬аdrugs have been developed that possess the analgesic properties of morphine and heroin. These drugs, which include┬аmeperidine┬а(Demerol),┬аmethadone, levorphonal, and many others, are known as synthetic opioids. They have largely replaced morphine and heroin in the┬аtreatment┬аof severe pain.
Opiates achieve their effect on the brain because their structure closely resembles that of certain molecules called┬аendorphins, which are naturally produced in the body. Endorphins suppress pain and┬аenhance┬аmood by occupying certain┬аreceptor┬аsites on specific┬аneurons┬а(nerve cells) that are involved in the transmission of nervous impulses. Opiate alkaloids are able to occupy the same receptor sites, thereby mimicking the effects of endorphins in suppressing the transmission of pain impulses within the nervous system.
History of opium
The opium poppy was native to what is now┬аTurkey. Ancient Assyrian herb lists and medical texts refer to both the opium poppy plant and opium, and in the 1st century┬аCE┬аthe Greek physician┬аDioscorides┬аdescribed opium in his┬аtreatise┬аDe materia medica, which was the leading Western text on┬аpharmacology┬аfor centuries. The growth of poppies for their opium content spread slowly eastward from┬аMesopotamia┬аand┬аGreece. Apparently, opium was unknown in either┬аIndia┬аor┬аChina┬аin ancient times, and knowledge of the opium poppy first reached China about the 7th century. At first, opium was taken in the form of pills or was added to beverages. The oral intake of raw opium as a medicine does not appear to have produced widespread addictions in ancient Asian societies.
Opium┬аsmoking┬аbegan only after the early Europeans in┬аNorth America┬аdiscovered the Indian practice of┬аsmoking tobacco┬аin pipes. Some smokers began to mix opium with tobacco in their pipes, and smoking gradually became the preferred method of taking opium. Opium smoking was introduced into China from┬аJava┬аin the 17th century and spread rapidly. The Chinese authorities reacted by prohibiting the sale of opium, but these edicts were largely ignored. During the 18th century European traders found in China an expanding and profitable market for the drug, and the┬аopium trade┬аenabled them to acquire Chinese goods such as┬аsilk┬аand┬аtea┬аwithout having to spend┬аprecious┬аgold and┬аsilver. Opium addiction became widespread in China, and the Chinese governmentтАЩs attempts to prohibit the import of opium from British-ruled India brought it into direct conflict with the British government. As a result of their defeat in the┬аOpium Wars, the Chinese were compelled to legalize the importation of opium in 1858. Opium addiction remained a problem in Chinese society until the Communists came to power in 1949 and┬аeradicated┬аthe practice.
In the West, opium came into wide use as a painkiller in the 18th century, and opium, laudanum, and┬аparegoric┬аwere active ingredients in many patent medicines. These drugs were freely available without legal or medical restrictions, and the many cases of addiction they caused did not arouse undue social concern. Morphine was first isolated from opium about 1804, and the hypodermic syringe was invented at mid-century. Their use in combination on hundreds of thousands of sick or wounded American soldiers in the┬аCivil War┬аproduced┬аunprecedented┬аnumbers of addicts. Heroin, which was first synthesized in 1898, proved even more addictive than morphine, and by the early decades of the 20th century the legal use of opiates of any kind had been curtailed. The traffic in such drugs then went underground, leading to a vast illicit trade in heroin.
Although opium trade routes extending from the southeastern and southwestern regions of Asia closed temporarily during┬аWorld War II, cultivation of the plant continued and even prospered in areas of China. In 1948 Burma (Myanmar), located along the southwestern border of China, gained independence and soon after emerged as a major producer of the drug, paralleling the suppression of opium cultivation in China. Throughout the 1960s and тАЩ70s,┬аSoutheast Asia┬аexperienced substantial growth in illicit opium trade. The border area shared by Myanmar,┬аLaos, and┬аThailand┬аeventually became known as the┬аGolden Triangle, a region that by the mid-1990s was the worldтАЩs leader in opium cultivation.
Smoking of opium declined in the 20th century, partly because it had been supplanted by more-potent derivatives and partly because of determined efforts in China and other developing countries to┬аeradicate┬аit. In the late 1990s, drug-control programs headed by the┬аUnited Nations┬аand by individual governments contributed to a reduction in opium poppy cultivation in the Golden Triangle. However, the region subsequently became a major producer of other illicit substances, including┬аmethamphetamines.
Also in the late 1990s, opium poppy cultivation increased in┬аAfghanistan, and that country became a leading producer of heroin. As cultivation of the plant continued to soar there in the early 2000s, drug trade in the region became associated with terrorism and lawlessness. Near the end of the decade, however, increased law enforcement efforts and the outbreak of a poppy┬аfungal disease┬аcaused poppy cultivation and opium production in Afghanistan to drop significantly. As a result, opium prices increased across the region, threatening to undermine the countryтАЩs illegal opium and heroin trade. The declines were seen as an opportunity to persuade local farmers to┬аcultivate┬аlegal crops. Because of Internet pharmacies that sold the drug illegally, however, global opium trafficking remained high.
The┬аlegitimate┬аuse of certain opiate alkaloids in medicine has┬аcompounded┬аissues surrounding the cultivation of opium poppies. Today┬аP. somniferum┬аis legally grown in some areas for the production of medicinal alkaloids. However, unlicensed cultivation of opium plants remains a serious legal offense in many countries, including the┬аUnited States, since the substance is the starting product for heroin, which has millions of addicts worldwide. Opium Drug Physiological Actions & History Opium Drug Physiological Actions & History Opium Drug Physiological Actions & History