0-Adrenergic agents

Epinephrine and NE belong to the chemical class of substances known as the catecholamines. This name was given to these compounds because they contain an amino group attached to an aromatic ring that contains two hydroxyl 

Epinephrine and NE each pos.scss a chiral carbon ntom. thus, each can exist as an enantiomeric pair of isomers. Hz enantiomer with the (K) configuration is biosynthesized f-i the body and po.sscsscs the biological activity. 

The action of NE at adrenergic receptors is terminated by a combination of processes, including uptake into Ihe neuron and into cxtraneuronal lis.sucs. diffusion away from the synapse. and metabolism. Usually. Ihe primary mechanism for termination of Ihe action of NE is rcuplakc of the catecholamine into tlie nerve terminal. This procc.ss is termed upuike-l and involves a Na /Cl -dcpendenl transmembrane transporter that has a high affinity for NE. This uptake system also transparts certain amines other than NE into the 

The two principal en/ymes involved in catecholamine metabolism are monoamine oxida.se (MAO) and catechol-O-methyltransferasc (COMT). Both of these cn/.ymes are distributed throughout the body, with high concentrations found in the liver and kidneys. MAO is ass x ialed primarily 

Mcthylation by COMT occurs almost exclusively on the mrhi-hydroxyl group of the catechol, regardless of whether ihe catechol is NE, epinephrine, or one of the metabolic products. For example, the action of COMT on NE and epinephrine gives normetanephrine and metanephrine. respectively. A converging pattern of NE metabolism of NE and epinephrine in which 3-mcthoxy-4-hydroxymandelic acid and T-methoxy-d-hydroxyphcnylethylcnc glycol are common end products thus occurs, regardle.ss of whether the first metabolic step is oxidation by MAO or mcthylation by COMT. 

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A tetrahydronaphtAaleneamine derivative, 2-(5,6,7,8-tetraliydro-l-naphthaleneamiQe)-2-knidazoliQe (12), is used ia the hydrochloride form as an adrenergic agent, ie, trama2oline hydrocholoti.de, also called KB 227 and Rhinaspray. 

When a patient is to receive an adrenergic agent for shock, the nurse obtains the blood pressure, pulse rate and quality, and respiratory rate and rhythm. The nurse assesses the patient s symptoms, problems, or needs before administering the drug and records any subjective or objective data on the patient s chart. In emergencies, the nurse must make assessments quickly and accurately. This information provides an important database that is used during treatment. 

Pj-Adrenergic agents Pj-Agonists can be used as aerosois when airway reactions are predominant... 

This peripheral activity may be a rational basis for the use of systemic local anaesthetics in neuropathic states since ectopic activity in damaged nerves has been shown to be highly sensitive to systemic sodium channel blockers. This too is probably part of the basis for the analgesic effects of established effective anti-convulsants that block sodium channels such as carbamazepine, although central actions are important and may even predominate. The precise actions of excitability blockers therefore remains hazy as does any clear basis for the effectiveness of antidepressants and other adrenergic agents in the treatment of neuropathic pain as both central and peripheral actions, including sympathetic effects are possible. 

Because of their limited effects on allergic symptoms, decongestants often are used in combination with antihistamines.8 Many antihistamines are available in fixed-dose combinations with pseudoephedrine, which enhances the reduction in nasal congestion and allows for the patient convenience of one tablet. Optimally, therapy should be initiated with an antihistamine alone, adding the adrenergic agent only if nasal congestion does not resolve with antihistamine monotherapy. Use of separate antihistamine and pseudoephedrine also permits independent dose titration.4,11,12... 

Norepinephrine is a potent a-adrenergic agent with less pronounced P-adrenergic activity. Doses of 0.01 to 3 mcg/kg per minute can reliably increase blood pressure with small changes in heart rate or cardiac index. Norepinephrine is a more potent agent than dopamine in refractory septic shock.24,27-28... 

Dopamine is a a- and P-adrenergic agent with dopaminergic activity Low doses of dopamine (1 to 5 mcg/kg per minute) maintain renal perfusion, higher doses (greater than 5 mcg/kg per minute) exhibit a- and P-adrenergic activity and are frequently utilized to support blood pressure and to improve cardiac function. Low doses of dopamine should not be used for renal protection as part of the treatment of severe sepsis.24,27-28... 

Direct alkylation of the appropriate aryl-ethanolamine is, of course, widely used as, for example, in treatment of ephedrine (13a) with ethyl iodide to give the adrenergic agent, etafedrine (13b), or with cinnamyl chloride to give the muscle relaxant, cinnamedrine (14).10 Likewise, alkylation... 

Amidephrine (25), an adrenergic agent very closely related to m talol, finds use as a broncho-dilator. -5 Carbuterol (27), another bronchodilator, is made by reacting 3-amino-4-benzyloxyacetophenone with phosgene to give isocyanate 26. Subsequent... 

Norepinephrine is a potent a-adrenergic agent (0.01 to 3 mcg/kg/min) that is useful as a vasopressor to restore adequate blood pressure after failure to restore adequate blood pressure and organ perfusion with... 

Cycloaddition (13,326).2 The azomethine ylide (a) generated with LDA from trimethylamine oxide adds stereoselectively to the dihydronaphthalenes 1 to provide the benzisoindoiines 2, of use as a-adrenergic agents in therapy. 

Acetylenes, hydration, 20 "Acid", 476 Additive effects of substituents, 179 Adrenalin, 38 Adrenalone, 38 Adrenergic agents, 36, 37 Adrenergic agonists, SAR, 37, 38, 251... 

Drugs that may interact with linezolid include monoamine oxidase inhibitors, SSRIs, and adrenergic agents (eg, dopamine, epinephrine). 

Concomitant therapy Cholinesterase inhibitors may be used in combination with adrenergic agents, -blockers, carbonic anhydrase inhibitors, or hyperosmotic agents. 

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