Sympathomimetics norepinephrine

As of the mid-1990s, use of MAOIs for the treatment of depression is severely restricted because of potential side effects, the most serious of which is hypertensive crisis, which results primarily from the presence of dietary tyramine. Tyramine, a naturally occurring amine present in cheese, beer, wine, and other foods, is an indirecdy acting sympathomimetic, that is, it potently causes the release of norepinephrine from sympathetic neurons. The norepinephrine that is released interacts with adrenoceptors and, by interacting with a-adrenoceptors, causes a marked increase in blood pressure the resultant hypertension may be so severe as to cause death. 

The sympathetic or adrenergic nervous system operates in juxtaposition to the parasympathetic nervous system to maintain homeostasis in response to physical activity and physical or psychological stress. Sympathomimetic neurotransmission is generally mediated by norepinephrine [51-41 -2] (1), CgH NO, released from presynaptic storage granules upon stimulation. A second endogenous sympathomimetic agent, epinephrine [51-43-4] (2),... 

Compounds stmcturaHy related to the endogenous sympathomimetic amines epinephrine and norepinephrine have classically been employed as appetite suppressants. These agents, of which amphetamine [300-62-9], is the prototypical example, generally retain the phenethyl amine, but lack... 

Adrenergic dru mimic the activity of the sympathetic nervous system. These dragp also are called sympathomimetic druc s. Epinephrine and norepinephrine are neurohormones produced naturally by the body. Synthetic preparations of these two neurohormones,... 

The answer is local anesthetic properties it can block the initiation or conduction of a nerve impulse. It is biotransformed by plasma esterases to inactive products. In addition, cocaine blocks the reuptake of norepinephrine. This action produces CNS stimulant effects including euphoria, excitement, and restlessness Peripherally, cocaine produces sympathomimetic effects including tachycardia and vasoconstriction. Death from acute overdose can be from respiratory depression or cardiac failure Cocaine is an ester of benzoic acid and is closely related to the structure of atropine. 

The answer is b. (Kn.lzu.ng, p 5.38.) Crack is the free-base (nonsalt) form of the alkaloid cocaine. It is called crack because, when heated, it makes a crackling sound. Heating crack enables a person to smoke it the drug is readily absorbed through the lungs and produces an intense euphoric effect in seconds Use has led to seizures and cardiac arrhythmias. Some of cocaine s effects (sympathomimetic) are due to blockade of norepinephrine reuptake into presynaptic terminals it does not block receptors. Flashbacks can occur with use of LSD and mescaline but have not been associated with the use of cocaine. 

Norepinephrine (an cq, a2, and Pi agonist) demonstrated higher resuscitation rates compared to epinephrine in one study (64% vs. 32%) but no significant difference in survival to hospital discharge. Consequently, epinephrine remains the first-line sympathomimetic for CPR. 

Autonomic Cocaine has stong sympathomimetic effects due to inhibition of norepinephrine reuptake, and perhaps central mechanisms as well. Effects include those typical of sympathetic autonomic activation. Cardiovascular and cerebrovascular effects are prominent. 

Absence of one or both aromatic hydroxyl groups is associated with an increase in indirect sympathomimetic activity, denoting the ability of a substance to release norepinephrine from its neuronal stores without exerting an agonist action at the adrenoceptor (p. 88). 

Tyramine, the only indirect-acting compound, exhibits sympathomimetic effects by causing the release of endogenic norepinephrine, and it has only found practical use in experiments. It inactivates monoaminooxidase very quickly. It has no practical clinical use. 

Ephedrine is an alkaloid that is present in various forms of the ephedrine family, and which is still extracted from Ephedra sinica and Ephedra equisetina. Because of the presence of two asymmetric atoms, there are four isomeric forms. Pseudoepinephrine (d-isoephrine) is a stereoisomer with pharmacological action that differs slightly from ephedrine. The pharmacological action of ephedrine is typical of noncatecholamine sympathomimetics of mixed action. It stimulates both a- and 8-adrenoreceptors, and simultaneously causes a release of norepinephrine from synaptic neurons. Its vasoconstrictive ability is approximately 100 times weaker than that of epinephrine however, the duration of action is approximately 10 times longer. It is much less toxic than epinephrine, which allows it to be used widely in medicine. 

Metaraminol is a sympathomimetic amine of both direct and indirect action that has hemodynamic characteristics similar to norepinephrine. It has the ability to elevate both systohc and diastolic blood pressure. 

As drugs of mixed action, amphetamines activate adrenergic receptors and simultaneously release endogenic catecholamines (norepinephrine and dopamine) from neurons of the brain and periphery. Sympathomimetic effects on the periphery are very similar to those of ephedrine. Amphetamine elevates systolic and diastolic blood pressure and has weakly expressed, broncholytic action. These effects are more prolonged, yet less expressed, than with epinephrine. The distinctive feature of amphetamines is their psychostimulatory activity. Larger doses can cause hallucinations and mental conditions similar to paranoid schizophrenia. As a sympathomimetic, amphetamine is sometimes used for uterine inertia. Synonyms of amphetamine are phenamine and benzedrine. 

Pharmacology Amphetamines are sympathomimetic amines with CNS stimulant activity. CNS effects are mediated by release of norepinephrine from central noradrenergic neurons. Peripheral activities include elevation of systolic and diastolic blood pressures and weak bronchodilator and respiratory stimulant action. Pharmacokinetics ... 

Uses Endogenous depression Action TCA T synaptic CNS levels of serotonin /or norepinephrine Dose Adults. 25 mg PO tid-qid >150 mg/d not OK Elderly. 10-25 mg hs Peds. 6-7 y 10 mg/d 8-11 y 10-20 mg/d >11 y 25-35 mg/d, 4- w/ hepatic insuff Caution [D, +/-] NAG, CV Dz Contra TCA allergy, use w/ MAOI Disp Caps, soln SE Anticholinergic (blurred vision, retention, xerostomia) Interactions T Effects W/ antihistamines, CNS depressants, cimetidine, fluoxetine, OCP, phenothiazine, quinidine, EtOH T effects OF anticoagulants T risk of HTN W/clonidine, levodopa, sympathomimetics T effects W/barbiturates, carbamazepine, rifampin EMS Concurrent use w/ MAOIs have resulted in HTN,... 

Drugs that mimic the actions of acetylcholine are termed cholinomimetic, and those that mimic epinephrine and/or norepinephrine are adrenomimetic. The cholinomimetic drugs are also called parasympathomimetic drugs. The adrenomimetic drugs are often called sympathomimetic. 

B) Indirect sympathomimetic effects in the periphery due to release of norepinephrine... 

J. Ermert, K. Hamacher, H.H. Coenen, Convenient synthesis route to n.c.a F-labelled sympathomimetics based on norepinephrine, J. Label. Compd. Radiopharm. 40 (1997) 53-56. 

Mechanism of Action A sympathomimetic amine that produces CNS and respiratory stimulation, mydriasis, bronchodilation, a pressor response, and contraction of the urinary sphincter Directly effects alpha and beta receptor sites in peripheral system. Enhancesreleaseof norepinephrine by blocking reuptake, inhibiting monoamine oxidase. Therapeutic Effect Increases motor activity, mental alertness decreases drowsiness, fatigue. 

Mechanism of Action A sympathomimetic amine that stimulates the release of norepinephrine and dopamine. Therapeutic Effect Decreases appetite. Pharmacokinetics Rapidly absorbed from the gastrointestinal (GI) tract. Widely distributed. Metabolized in liverto active metabolite and undergoes extensive first-pass metabolism. Excreted in urine. Unknown if removed by hemodialysis. Half-life 4-6 hr. 

Mecfianism of Action A phenylalkylamine sympathomimetic with activity similar to amphetamines that stimulates the central nervous system (CNS) and elevates blood pressure (BP) most likely mediated via norepinephrine and dopamine metabolism. Causes stimulation of the hypothalamus. Therapeutic Effect Decreases appetite. Pharmacokinetics The pharmacokinetics of phendimetrazine tartrate has not been well established. Metabolized to active metabolite, phendimetrazine. Excreted in urine. Half-life 2-4 hr. 

Mechanism of Action A sympathomimetic amine structurally similar to dextroamphetamine and is most likely mediated via norepinephrine and dopamine metabolism. Causes stimulation of the hypothalamus. Therapeutic Effect Decreased appetite. 

Weiner, N. (1991) Drugs that inhibit adrenergic nerves and block adrenergic receptors. In Gilman, A. and Goodman, L., eds. Norepinephrine, Epinephrine and the Sympathomimetic Amines, 7th ed. New York The Pharmacological Basis of Therapeutics, pp. 145-180. 

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