Decongestant, ephedrine central nervous system

Many alkaloids have pronounced biological properties, and a substantial number of the pharmaceutical agents used today are derived from naturally occurring amines. As a few examples, morphine, an analgesic agent, is obtained from the opium poppy Papaver somnifemm. Cocaine, both an anesthetic and a central nervous system stimulant, is obtained front the coca bush Erythroxylon coca, endemic to upland rain forest areas of Colombia, Ecuador, Peru, Bolivia, and western Brazil. Reserpine, a tranquilizer and antihypertensive, comes from powdered roots of the semitropical plant Rauwolfia serpentina. Ephedrine, a bronchodilator and decongestant, is obtained front the Chinese plant Ephedra sinica. 

Ephedrine has not been extensively studied in humans despite its long history of use. Its ability to activate 3 receptors probably accounted for its earlier use in asthma. Because it gains access to the central nervous system, it is a mild stimulant. Ingestion of ephedrine alkaloids contained in ma huang has raised important safety concerns. Pseudoephedrine, one of four ephedrine enantiomers, has been available over the counter as a component of many decongestant mixtures. However, the use of pseudoephedrine as a precursor in the illicit manufacture of methamphetamine has led to restrictions on its sale. 

Amphetamine was the first anorectic drug to be introduced into clinical practice. It was originally synthesised in the 1920 s as a potential substitute for ephedrine and marketed under the trade name of Benzedrine for use as a nasal decongestant. Initially, it was thought to have very little, if any, effect on the central nervous system. However, within a relatively short time it was noted that, in contrast to what had first been thought, amphetamine had pronounced stimulant and mood elevating properties. 

The pharmacokinetic and toxicokinetic behavior of any isomer cannot be used to predict that of any other ephedrine isomer. Methamphetamine is a prime example. The d-isomer is a potent, and quite dangerous, central nervous system (CNS) stimulant. The 1-isomer is merely a decongestant. There is a tendency in the literature, particularly in government monographs, to lump together all "ephedrine alkaloids." Doing so is both foolish and misleading, as it implies that the toxicity of all the enantiomers is equivalent, which is clearly not the case. 

Ephedrine and neosynephrine are used as decongestants in cough syrups and nasal sprays. They cause shrinking of the membranes that line the nasal passages. These compounds are related to two chemicals that are important to the functioning of the central nervous system, L-dopa and dopamine, which are described in Section 16.5. 

Ephedrine, a central nervous system stimulant, is used in nasal sprays as a decongestant. This compound is a weak organic base ... 

Amphetamine, methamphetamine and ephedrine all have similar structures and each has two enantiomers. Amphetamine is a central nervous system stimulant and an anorexic. Methamphetamine is also an anorexic and is frequently used for treating attention disorders with hyperactivity. Ephedrine, on the other hand, although of similar structure has quite different physiological effects. Ephedrine (1) is a commonly used as a bronchodilator whereas (d) ephedrine (pseudoephedrine) is used as a decongestant. The separation of the six isomers of amphetamine, methamphetamine and ephedrine is shown in figure 6.17. 

Ephedrine is a sympathomimetic or central nervous system stimulant. It is a potent stimulator of a, pi and p2 adrenergic receptors. The effects include vasoconstriction, raised blood pressure and pulse, bronchodilation and diuresis. Ephedrine-based drugs are used as nasal decongestants, bronchodilators and in anaphylactic shock. In excess they cause insomnia, tachycardia and dizziness. 

Notably, pseudoephedrine is a diastereomer of ephedrine and considerably racemic ephedrine (dl-ephedrine) has not been found naturally, however, it is prepared synthetically and is inactive for commercial purposes. Ephedrine and pseudoephedrine are completely stable compounds under changing temperature conditions, but they are quite unstable when exposed to sunlight or in the presence of oxygen pressure [2]. The unique molecular structure of ephedrine causes its different stereoisomers to be valuable for pharmaceutical applications such as nasal decongestant, pupil dilator, bronchodilator, and central nervous system stimulant. Ephedrine is a sympathomimetic substance and the principle mechanism of ephedrine activity is its influence, by enhancing the activity of noradren-alin, on post-synaptic a- and (3-receptors in the nervous system. Stimulation of a 1-adrenergic receptors produces contraction of vascular smooth muscle. 

Whereas (—)-ephedrine was harmed for use as a dietary supplement by the FDA, it was reported in a patent by Warner Lambert in 1999 that (+ )-ephedrine may be useful as a decongestant and appetite suppressant without the side effects on the central nervous system (CNS) that is seen for the natural (-)-ephedrine enantiomer. Of course, Pseudoephedrine (Sudafed) is an over-the-counter medication in the United States widely used to treat nasal congestion associated with colds or the flu. The enantiomer (+ )-pseudoephedrine has also been patented by Warner Lambert as a decongestant with fewer... 

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