Amphetamine pharmacological properties

Pemoline is a structurally unique CNS stimulant that exhibits minimal sympatomimetic effects, and possesses the same pharmacological properties as amphetamines and methylphenidate, yet it has less potential to cause addiction than other CNS stimulators. It enhances vigilance and motor activity, and causes weak euphoria, which is possibly linked to an increase in dopaminergic transmissions in CNS structures. 

Diethylpropion possess basically the same pharmacological properties as amphetamines and is used in treating obesity by limiting caloric intake.Synonyms of this drug are amphepramone, anorex, adiposon, regenon, tenuate, tepanil, and others. 

EDS is usually treated using amphetamine-like CNS stimulants or modaflnil, a novel wake-promoting compound unrelated to amphetamines. The most commonly used amphetamine-like compounds aremethamphetamine, D-amphetamine, methylpheni-date, pemoline, and mazindol. The most important pharmacological property of these compounds is to release catecholamines, i.e., dopamine and norepinephrine. Amphetamine-like compounds also share the property of blocking the reuptake and the degradation of these monoamines (monoamine oxidase inhibition at high doses). All these properties presynaptically enhance dopamine transmission, which are likely to contribute to the EEG arousal effects of amphetamines. 

Methylphenidate shares the pharmacological properties and the abuse potential of the amphetamines. When given intravenously, it activates psychotic symptoms in schizophrenic patients if administered during the active phase of their illness, but not after remission. It failed to produce a psychotic reaction in most manic or depressed patients or in healthy subjects (27). Adults with childhood-onset ADHD had an earlier onset of psychoactive substance use disorders, independent of any psychiatric co-morbidity (33). However, bipolar disorders conferred a significantly increased risk for early onset psychoactive substance use disorders independent of ADHD. The question arises as to the contribution of stimulant treatment to psychoactive substance use disorders. There were no differences in medicated versus unmedicated adolescents with ADHD in a review of eight outcome studies comprising 580 adolescents briefly treated with stimulants for six months to five years (34). 

Phentermine has a quaternary carbon atom with one methyl oriented like the methyl of fSl-amphelamine and one methyl oriented like the methyl of f/U-amphetamine. and it reportedly has pharmacological properties of both the (R) and (S) isomers of amphetamine. The compound is u.sed as an appetite supprc.s.sant and is a Schedule IV agent, indicating less abu.se potential than dextroamphetamine. 

These effects are produced mostly by phenylpropanolamines present in the leaves. These include cathinone [4] (5 -a-aminopropiophenone), cathine [5] [(-)-IS, 2S-norpseudoephedrine] and (-) -IR, 2S-norephedrine (8). These substances have pharmacological properties similar to those of amphetamine [6] (81), as they induce the release and inhibit the uptake of dopamine and norepinephrine in CNS (82). In addition to the known phenylpropylamines, the presence of other amines such as meracathine, pseudomeracathine and meracathinone have been identified (83, 84). Cathinone, being a ketoamine base, is extremely unstable and, in particular, it can be transformed into (+)-norpseudoephedrine and (-)-norephedrine by an enzymatic reduction. It can also be oxidized to give 1-phenyl-l,2-propandione, while the cathinone dimers, such as 3,6-dimethyl-2,5-diphenylpyrazine are purely artifacts of the isolation (85). 

Methylphenidate is a piperidine derivative that is structurally related to amphetamine. Methylphenidate (Ritalin, others) is a mild CNS stimulant with more prominent effects on mental than on motor activities. However, large doses produce signs of generalized CNS stimulation that may lead to convulsions. Its pharmacological properties are essentially the same as those of the amphetamines. 

The kinetics of excretion are a direct consequence of the kinetics of metabolic transformations. The faster a drug is metabolized, the faster its elimination can be expected. In accordance with this assertion, rats given R,S( ), S(-t-), and R(-)-amphetamine, were found to excrete less (-t-)-p-hydroxy-amphetamine than its (- )-isomer this may be the basic explanation of the more pronounced pharmacological properties of the dextro-, compared with the levo-amphe-tamine. For the hypnotic agent hexobarbital, the elimination half-life in man is about three times longer for the... 

A review article on certain aspects of the pharmacological properties of most of the iboga alkaloids has appeared (41). Several compounds stimulated the central nervous system in a way which was not amphetamine-like and manifested itself in a number of cases as antagonism against the reserpine catalepsy. Many of the compounds caused hypotension and bradycardia in anesthetized cats. Under these conditions ibogaline was the most active alkaloid. Coronaridine is said to produce a significant diuresis (42) and catharanthine has some hypoglycemic activity (43). 

The pharmacologic properties of (—)-cathinone are similar to those of (+)-amphetamine, and both alkaloids possess central nervous system (CNS) excitatory activity and indirect neuronal excitement activity. That is to say, both alkaloids are incorporated at the sympathetic nerve ending and expel noradrenaline (NAdr = norepinephrine, NE) from the amine storage granule, and the expelled NE works as the effector. These activities seem to be the effects caused by chewing khat [11]. Cathine also possesses CNS excitatory activity, but the activity of cathine is less than that of cathinone [12]. 

Amphetamine derivatives (l-arylpropan-2-amines) represent a subclass of chiral amines with interesting pharmacological properties. Most of them show central and peripheral stimulant activity by means of multiple actions at serotonin (5-HT) receptor subtypes, and their applications cover, for instance, the treatment of sleep disorders. 

Chewing leaves of the khat shrub is practiced in parts of East Africa and the Arabian peninsula (Kalix 1988 Widler et al. 1994). Some estimate daily use at 5 million portions. Use in the West is less common, but has increased somewhat. More common in the United States has been use of the synthetic drug methcathinone (or "cat"), which is derived from khat alkaloids. Only the fresh khat leaves are pharmacologically active, so for some time use was limited to local areas that grew the plant. However, with air transportation, use has spread with emigrants in Europe and the United States. Because of its pharmacological similarities to amphetamine and its addictive properties, khat has been listed on Schedule I of the United Nations Convention on Psychotropic Substances. 

Cocaine is a local anesthetic with a peripheral sympathomimetic action that results from inhibition of transmitter reuptake at noradrenergic synapses (see Chapter 6 Introduction to Autonomic Pharmacology). It readily enters the central nervous system and produces an amphetamine-like effect that is shorter lasting and more intense. The major action of cocaine in the central nervous system is to inhibit dopamine reuptake into neurons in the "pleasure centers" of the brain. These properties and the fact that it can be smoked, "snorted" into the nose, or injected for rapid onset of... 

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