A-Sympathomimetics

Tetrahydro2oline [84-22-0] 2-(l,2,3,4-tetrahydro-l-naphthyl)2-imida2olin, (Tysine, Visine) (40), a sympathomimetic and nasal decongestant, is made by the condensation of 1,2,3,4-tetrahydro-l-naphthoic acid or its methyl ester with 1,2-ethylenediamine. 

Acutrim 16 Hour Steady Control Tablets. Acuttim is an appetite suppressant diet aid available without a prescription and marketed by CIBA Consumer Pharmaceuticals. The active ingredient is phenylpropanolamine hydrochloride [154-41 -6] a sympathomimetic amine (see Antiobesity drugs). Acutrim dehvers its dosage at a precisely controlled rate for up to 16 hours. This is achieved through the OROS technology. 

Administration of a sympathomimetic bronchodilator may result in restlessness, anxiety, increase in blood pressure, palpitations, cardiac arrhythmias, and insomnia When these dragp are used by inhalation, excessive use (eg, over the recommended times) may result in paradoxical bronchospasm. 

PATIENTS TAKING CORTICOSTEROID INHALANTS If the patient is receiving a sympathomimetic bronchodilator by inhalation and a corticosteroid such as triamcinolone by inhalation, die nurse administers the bronchodilator first, waits several minutes, then administers die corticosteroid inhalant. When administering two inhalations of die same drug, it is advisable to wait at least 1 minute between puffs. 

In contrast to this, there are no such structural constraints on a-adrenergic agonists or antagonists. Some of the most active a-sympathomimetic agents in fact contain an imidazoline moiety as part of the pharmacophore. The appropriate ring system can be... 

Midrin is a proprietary combination of acetaminophen, isometheptene mucate (a sympathomimetic amine), and dichloralphenazone (a chloral hydrate derivative) that has shown modest benefits in placebo-controlled trials. It may be an alternative for patients with mild to moderate migraine... 

It is established that nicotine is a sympathomimetic agent and is expected to enhance physiologic and biochemical stress responses however, smokers reports do not comply with this explanation. This phenomenon is referred to as Nesbitt s paradox (Parrott 1998). Does nicotine normalize behavior of subjects under stress (Acri 1994) ... 

Adrenaline (epinephrine) is a sympathomimetic agent that causes bronchodilatation. It is used to relieve bronchospasm in anaphylactic shock reactions. Histamine, kinins and prostaglandins, such as prostaglandin E2, are inflammatory mediators. In response to allergic stimuli, inflammatory mediators may cause bronchoconstrictions. Guaifenesin is an expectorant preparation that increases bronchial secretions to promote the expulsion of the mucus coughed up. 

Oxymetazoline. Is a sympathomimetic (this is much like psychotomimetic), orally active at 5 to 10 mg per kilogram of body weight. 

Vasoconstriction. Local application of a-sympathomimetics can be employed in infiltration anesthesia (p. 204) or for nasal decongestion (naphazoline, tetra-hydrozoline, xylometazoline pp. 90, 324). Systemically administered epinephrine is important in the treatment of anaphylactic shock for combating hypotension. 

Since structural requirements for high affinity, on the one hand, and oral applicability, on the other, do not match, choosing a sympathomimetic is a matter of compromise. If the high affinity of epinephrine is to be exploited, absorbability from the intestine must be foregone (epinephrine, isoprenaline). If good bioavailability with oral administration is desired, losses in receptor affinity must be accepted (etilefrine). 

Vasoconstriction induced by an a-sympathomimetic is followed by a phase of enhanced blood flow (reactive hyperemia, A). This reaction can be observed after the application of a-sympa-thomimetics (naphazoline, tetrahydro-zoline, xylometazoline) to the nasal mucosa. Initially, vasoconstriction reduces mucosal blood flow and, hence, capillary pressure. Fluid exuded into the interstitial space is drained through the veins, thus shrinking the nasal mucosa. 

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. 

EPHEDRINE SULFATE Ephedrine sulfate is a sympathomimetic alkaloid that stimulates alpha and beta receptors as well as the CNS. It is effective orally and parenterally. It is less potent than epinephrine. 

Usual dose response Advise patients to contact a physician if they do not respond to their usual dose of a sympathomimetic amine. 

C. The vasodilation produced by drug Y is antagonized by timolol, a (3-receptor antagonist. Although bradykinin, histamine, acetylcholine, and isoproterenol will all cause vasodilation, only isoproterenol does so by activating p-receptors. Phenylephrine is a sympathomimetic that is selec-... 

Mechanism of Action A sympathomimetic that stimulates betaj-adrenergic receptors in the lungs, resulting in relaxation of bronchial smooth muscle. Therapeutic Effect Relieves bronchospasm and reduces airway resistance. 

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. 

Mechanism of Action A sympathomimetic (adrenergic agonist) that stimulates betai-adrenergic receptors. Therapeutic Effect Increases myocardial contractility, stroke volume, cardiac output. 

Mechanism of Action A sympathomimetic amine related to amphetamine and ephe-drine that enhances CNS stimulant activity. Peripheral actions include elevation of... 

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. 

Mechanism of Action A sympathomimetic, adrenergic agonist, t hat st i mulates betaj-adrenergic receptors in the lungs, resulting in relaxation of bronchial smooth muscle. Therapeutic Effect Relieves bronchospasm, reduces airway resistance. Pharmacokinetics Absorbed from bronchi following inhalaf ion. Metabolized in liver. Primarily excreted in urine. Unknown if removed by hemodialysis. Half-life 2-3 hr. 

MecHanism of Action A sympathomimetic that directly stimulates alpha-adrenergic and beta-adrenergic receptors. Therapeutic Effect Produces vasoconstriction of respiratory tract mucosa shrinks nasal mucous membranes reduces edema and nasal congestion. 

Mechanism of Action A sympathomimetic that directly acts on alpha-adrenergic receptors in arterioles of the nasal mucosa to produce vasoconstriction resulting in decreased blood flow. Therapeutic Effect Decreased nasal congestion. Pharmacokinetics Onset of acf ion occurs wif hin 5-10 minuf es for a duration of action of 5-6 hours. Well absorbed fhrough nasal mucosa. May also be systemically absorbed from bofh nasal mucosa and gasfroinfesfinal (GI) fracf. Half-life Unknown. 

The mechanisms by which 2-PAM exerts its cardiac effects have been studied in experimental animals. At least three classes of action have been attributed to the effects of altered calcium metabolism on autonomic ganglia. A sympathomimetic action of 2-PAM was postulated to explain the increase in blood pressure and the augmented myocardial contractility by one or more of the following mechanisms 2-PAM may not block the release of the endogenous compounds, but may prevent the uptake of catecholamine 1 it may stimulate the release of norepinephrine it Increases myocardial contractility by directly stimulating beta receptors and it increases blood pressure by directly stimulating alpha receptors. 5... 

It is a sympathomimetic amine, the mechanism of action is related to brain levels (or turnover rates) of serotonin or to increase glucose utilization. Its antiappetite effect is suppressed by serotonin blocking drugs. Its use in clinical practice is recently banned in India because of severe toxicity. 

Ephedrine is a sympathomimetic amine with direct and indirect effects on a, pi and 32 adrenoceptors 31=32>o). 

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