Ephedrine central nervous system

Omission of the side chain hydroxyl group from molecules based on epinephrine or ephedrine does not abolish the sympathomimetic activity of the resulting compounds. Many of these agents exert a considerable stimulant action on the central nervous system. As such, drugs in this class have been widely used—and... 

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. 

Due to its effect as a stimulant on the heart and central nervous system, ephedrine can cause heart problems, stroke, and other medical complications (including death). For this reason, there has been pressure to regulate or ban it in the United States, as was done with similar drugs. 

Synergy of unwanted pharmacological effect ginseng and its products will inhibit the central nervous system (CNS) when they are applied with luminal, chloral hydrate, or ephedrine, which can increase the release of dopamine, noradrenaline, and serotonin in the CNS thus inducing a hypertensive crisis if monoamine oxidase inhibitors (MAOIs) are given simultaneously. 

Ephedra, also known as Ma-Huang, is a central nervous system stimulant that is similar to amphetamine. Ephedra alkaloids (a material found in plants) with the active ingredient ephedrine have been used for medicinal purposes in China for... 

Adrenomimetic drugs with no substitutions on their benzene ring (e.g., amphetamine and ephedrine) are generally quite lipid soluble, readily cross the blood-brain barrier, and can cause central nervous system (CNS) stimulation. 

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 is a racemic mixture of phenylisopropylamine (Figure 9-4) that is important chiefly because of its use and misuse as a central nervous system stimulant (see Chapter 32). Pharmacokinetically, it is similar to ephedrine however, amphetamine even more... 

Ephedrine, given im/iv/sc, is indicated for the treatment of acute hypotensive states, treatment of Adams-Stokes syndrome with complete heart block, stimulation of the central nervous system (CNS) to combat narcolepsy and depressive states, treatment of acute bronchospasm, treatment of enuresis, and treatment of myasthenia gravis. When given in nasal form, ephedrine is used in the treatment of nasal congestion, promotion of nasal or sinus drainage, or relief of eustachian tube congestion. 

Pseudoephedrine and phenylpropanolamine [( )-norephedrine] are sympathomimetic agents with actions similar to those of ephedrine and are most commonly used for the relief of nasal congestion (363). Pseudoephedrine has been stated to have less pressor activity and central nervous system effects than ephedrine. 

Ma Huang has an anti-inflammatory activity (598). A survey for the active principle in the crude drug demonstrated that the most active one is pseudo-ephedrine. Ephedroxane was also isolated as a minor anti-inflammatory principle. The mechanism of the anti-inflammatory action of these compounds does not involve the central nervous system. Of several mechanisms considered, inhibition of prostaglandin E2 biosynthesis may be of great importance (398). 

Gordon Alles, the UCLA researcher who discovered amphetamine in 1927, was interested in MDA (3,4-methylenedioxyphenylisopropylamine) and its cousin 3,4-methylenedioxyphenylethylamine because of the structural closeness of these two molecules to ephedrine, the standard drug for testing central nervous system stimulation during the 1930s and 1940s. He decided that he would conduct what he called a "double-conscious test of these substances—meaning that he would synthesize, measure and take them himself in order to compare their effects with what he knew about how ephedrine affected him. 1 was quite well calibrated, he remarked later, "with 50 mg. doses of ephedrine and with similar doses of amphetamine. ... 

Figure 2.10 Amphetamine 30, methamphetamine 31, and methylenedioxymethamphetamine 32 (MDMA, ecstasy, XTC) are lipophilic compounds with good oral bioavailability they easily cross the blood-brain barrier to exert central nervous system effects. Dopamine 33, norepinephrine (noradrenalin) 34, and epinephrine (adrenaline) 35 are polar phenethylamines they have poor oral efficacy and do not pass the blood-brain barrier, producing only peripheral effects after intravenous application. Ephedrine 36 has intermediate lipophilicity besides its peripheral effects it also acts as a central stimulant. Although L-dopa 37 is even more polar than dopamine 33, it is orally active and crosses the blood-brain barrier by active transport mediated by the amino acid transporter.

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. 

Ephedrine and pseudoephedrine have more or less equivalent action on the respiratory tract, but ephedrine has greater central nervous system and pressor activity and is used in few products. 

Ephedrine is the predominant alkaloid of ephedra plants. Other phenylalanine-derived alkaloids found in ephedra plants are (+)-pseudoephedrine, (—)-norephedrine, (-l-)-norpseudoephedrine, (l)-A-methylephedrine and phenylpropanolamines. Ephedrine is a potent central nervous system (CNS) stimulant. Because ephedra is both an a- and p-adrenergic agonist, ingestion of quantities over 50 mg lead to a rise in blood pressure, heart rate and cardiac output. 

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