at 3rd and 4th position shows maximum alpha- and beta-adrenergic activity. Cross-reactivity Illegal drugs such as cocaine and MDMA also affect dopamine, serotonin, and norepinephrine. Norepinephrine is synthesized by the body from the amino acid tyrosine, and is used in the synthesis of epinephrine, which is a stimulating neurotransmitter of the central nervous system. Thus, all sympathomimetic amines fall into the larger group of stimulants (see psychoactive drug chart). In addition to intended therapeutic use, many of these stimulants have abuse potential, can induce tolerance, and possibly physical dependence, although not by the same mechanism(s) as opioids or sedatives. The symptoms of physical withdrawal from stimulants can include fatigue, dysphoric mood, increased appetite, vivid or lucid dreams, hypersomnia or insomnia, increased movement or decreased movement, anxiety, and drug craving, as is apparent in the rebound withdrawal from certain substituted amphetamines. Physical withdrawal from some sedatives can be potentially lethal, for instance benzodiazepine withdrawal syndrome. Opioid withdrawal is very uncomfortable, often described as a bad case of the flu, with possibly severe abdominal cramps and diarrhoea as central symptoms, but it is rarely lethal unless the user has a comorbid condition. Sympathomimetic drugs are sometimes involved in development of cerebral vasculitis and generalized polyarteritis nodosa like diseases involving immune-complex deposition. Known reports of such hypersensitivity reactions include the use of pseudoephedrine, phenylpropanlolamine, methamphetamine and other drugs at prescribed doses as well as at over-doses. Comparison "Parasympatholytic" and "sympathomimetic" have similar effects, but through completely different pathways. For example, both cause mydriasis, but parasympatholytics reduce accommodation (cycloplegia) while sympathomimetics do not. Examples amphetamine (Evekeo) benzylpiperazine (BZP) cathine (found in Catha edulis) cathinone (found in Catha edulis, khat) cocaine (found in Erythroxylum coca, coca) ephedrine (found in Ephedra) lisdexamfetamine (Vyvanse) maprotiline (Ludiomil) MDMA (Ecstasy, Molly) methamphetamine (Meth, Crank, Desoxyn) methcathinone methylenedioxypyrovalerone (MDPV) methylphenidate (Ritalin) 4-methylaminorex oxymetazoline (Afrin, Vicks Sinex) pemoline (Cylert) phenmetrazine (Preludin) propylhexedrine (Benzedrex) pseudoephedrine (Sudafed, SudoGest, also found in Ephedra species) Benzphetamine (Didrex) See also Adrenergic storm Sympathetic nervous system Sympatholytic References External links