Adrenergic-blocking activity

Bretylium (L) showed selective adrenergic blocking activity in animals and man but erratic absorption and other side effects limited its utility in hypertension (61). 

Drugs with a-adrenergic blocking activity are peripheral coronary-dilating agents that only differ in specificity with aj-adrenergic receptors. Prazozin and tetrazin are selective aj-adrenoblockers that are used in therapeutic doses to lower arterial pressure. 

Nonallergic bronchospasm (eg, chronic bronchitis, emphysema) n general, these patients should not receive propafenone or other agents with beta-adrenergic blocking activity. 

Pharmacology Labetalol combines both selective, competitive postsynaptic - -adrenergic blocking, and nonselective, competitive -adrenergic blocking activity. The - and -blocking actions decrease BP. Standing BP is lowered more than supine. 

Pharmacology Carvedilol, an antihypertensive agent, is a racemic mixture in which nonselective -adrenoreceptor blocking activity is present in the S(-) enantiomer and -adrenergic blocking activity is present in both R(+) and S(-) enantiomers at equal potency. Carvedilol has no intrinsic sympathomimetic activity. 

Hansch, C. and Lien, E. J. (1968) An analysis of the structure-activity relationship in the adrenergic blocking activity of the P-haloalkylamines. Biochem. Pharmacol. 17, 709-720. 

Unger, S. H. and Hansch, C. (1973) On model building in structure-activity relationships. A reexamination of adrenergic blocking activity of p-halo-p-arylakylamines. J. Med. Chem. 16, 745-749. 

D) Thioridazine has greater aj-adrenergic blocking activity than haloperidol. 

Both drugs are partial agonists at a-adrenergic receptors and at some serotonin and dopamine receptors they also can inhibit the release of endotheUal-derived relaxation factor. They may induce arterial vasoconstriction and have minor actions on the central nervous system. Their a-adrenergic blocking activity is relatively weak compared with those of other ergot alkaloids. 

Mechanism of Action An antihypertensive that possesses nonselective beta-blocking and alpha-adrenergic blocking activity. Causes vasodilation. Therapeutic Effect Reduces cardiac output, exercise-induced tachycardia, and reflex orthostatic tachycardia reduces peripheral vascular resistance. 

ANS They have varying degree of a adrenergic blocking activity. They also have weak anti-cholinergic, Hj-antihistaminic and anti 5-HT actions as well. 

It exerts potent presynaptic central a, adrenergic blocking activity which may cause increased noradrenaline release. It does not effect noradrenaline or 5-HT uptake in CNS. 

The Eg parameter was first introduced by Hansch and Lien into biological structure-activity studies 24). They showed that the adrenergic blocking activity of p-haloalkyl-... 

Propranolol Only (S)-form has jS-adrenergic blocking activity 178... 

Baxter, S.J., Jenkins, H.D.B. and Samuel, C.J. (1996). A Novel Computational Approach to the Estimation of Steric Parameters. III. Extension to Aliphatic Amines and Apphcation to the Adrenergic Blocking Activity of P-Haloalkylamine. Tetrahedron Lett., 37,4617-4620. 

Unger, S.H. and Hansch, C. (1973). On Model Building in Structure-Activity Relationships. A Reexamination of Adrenergic Blocking Activity of P-Halo-P-arylaIkyl2unines. J.Med.Chem., 16,745-749. 

Not all the parameters will necessarily be significant. For example, the adrenergic blocking activity of (3-halo- (3-arylamines (Fig. 9.13) was related to -rr and ct and did not include a steric factor ... 

Propanolol Racemic compound is used as drug however, only the (SFf-I-isomer has the desired P-adrenergic blocking activity... 

Leclerc, G., Mann, A., Wermuth, C. G., Bieth, N., Schwartz, J. Synthesis and (3-adrenergic blocking activity of a novel class of aromatic oxime ethers. J. Med. Chem. 1977, 20, 1657-1662. 

Esmolol is a class 11 antiarrhythmic agent with ultra-short-acting beta-adrenergic-blocking activity that is used (50 to 200 mcg/kg/minute) to treat supraventricular tachycardia such as atrial fibrillation or atrial flutter. It is rapidly metabolized by erythrocyte esterases via hydrolysis of the methyl ester. Unlike succinylcholine, esmolol is not metabolized by plasma cholinesterase (see also Eigures 67 and 83). 

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