Codeine physiological effects

Or they may be grouped according to the genus of their plant source (morphine and codeine, Section 23-2, are examples of opium alkaloids), or by their physiological effects (antimicrobials, antibiotics, analgesics), or by similarities in the route by which they are synthesized by the organism (biosynthesis). The structural and biosynthetic classifications make the most sense to the chemist and is the organization chosen here. 

The isolation of morphine from opium and the recognition of the significance of its physiological effects by F. W. A. Sertiirner in 1803-1817 as well as the first definition of the term alkaloid by Meissner in 1819-1821 have led to a rapid progress in the research of alkaloids (1). In the beginning of the past century, much attention was paid to the cultivated poppy plant Papaver somniferum L., which has been used since time immemorial in popular medicine. Of the so-far known 41 opium alkaloids, only morphine, codeine, and papaverine have found... 

Four neurotransmitters are acetylcholine, norepinephrine, dopamine, and serotonin. Epinephrine is also known as the flght-or-flight hormone. The amphetamines have structures similar to that of epinephrine. Alkaloids are nitrogen-containing compounds isolated from plants. They exhibit a variety of physiological effects on the body. Examples of alkaloids include nicotine, caffeine, quinine, atropine, morphine, and codeine. 

For many centuries morphine and codeine, alkaloids found in the oriental poppy plant, have been used as effective painkillers. Codeine, which is structurally similar to morphine, is used in some prescription painkillers and cough syrups. Heroin, obtained by a chemical modification of morphine, is strongly addicting and is not used medically. The structure of the prescription drug OxyContin (oxycodone) used to relieve severe pain is similar to heroin. Today, there are an increasing number of deaths from OxyContin abuse because its physiological effects are also similar to those of heroin. 

Methadone is frequently used to treat heroin, codeine, hydrocodone, oxycodone, and morphine addictions. Methadone when used as prescribed, is safe and effective and does not cause euphoric sensations but does relieve physical withdrawal symptoms and reduces physiologic cravings. Methadone does have side effects which may be intolerable to some patients. They include constipation, water retention, drowsiness, skin rash, excessive sweating, and change in sex drive. Methadone has been used successfully in the treatment of opioid addiction for over 30 years. 

The very positive nature of the oxidations for 1 and 2 make them unlikely participants in ET. However, other physiologically active compounds possess fairly positive oxidation potentials. For example, the tert-amine of amorphine 9 reacts at about 1.1 2 . It is reasonable to expect stabilization of the cation radical by transannular interaction with the benzenoid nucleus. An ET mechanism for the CNS effects has been proposed29 30, Related opium alkaloids in the codeine (a methyl ether of 9) class react in the range of 1.0 to 1.1 The psychotherapeutic agent... 

During heroin metabolism, the acetyl groups must be cleaved to yield morphine this might simply be hydrolysis or it may be an enzyme-mediated process. Codeine is also demethylated this is known to be an enzyme-mediated process (there are no simple chemical processes that would achieve this under physiological conditions), and some 10 %-15 % of the population are deficient in the enzyme, so codeine is not converted to morphine, and codeine has little analgesic effect for this group. Another 10 % of the population has overactivity of the enzyme, so that the codeine is demethylated very rapidly and effectively, and they must be careful not to consume an overdose, which would be less for them than for someone with more standard enzyme activity. Finally, in order to be excreted effectively in urine, the morphine is converted to a sugar derivative, to ensure water solubility. 

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