Sympatholytic agents

Mecfianism of Action An antiadrenergic, sympatholytic agent that stimulates betaj-adrenergic receptors in lungs. Therapeutic Effect Relaxes bronchial smooth muscle, relieves bronchospasm, reduces airway resistance. 

Mectianism of Action An antiadrenergic, sympatholytic agent that prevents pain signal transmission to the brain and produces analgesia at pre- and post-alpha-adrenergic receptors in the spinal cord. Therapeutic Effect Reduces peripheral resistance decreases BP and heart rate. 

Agents which block responses of effector cells to sympatho-adrenal stimuli may be termed adrenergic blocking agents. It is only at these effector cells that adrenergic mediators are involved in transmission of the nerve impulse. For a number of reasons, the frequently used terms adrenolytic and sympatholytic agents are ambiguous and undesirable (see 70). 

Hydralazine was one of the first orally active antihypertensive drugs marketed in the United States. Its structure is shown in Figure 12.4. Initially, the drug was used infrequently because of its propensity to produce reflex tachycardia and tachyphylaxis. However, with a better understanding of the compensatory cardiovascular responses that accompany use of arteriolar vasodilators (the drug has little or no effect on venous smooth muscle), hydralazine was combined with sympatholytic agents and diuretics with greater therapeutic success. 

The ester 16 has been converted in a series of steps to the amine 17, which on reaction with d-lysergic acid chloride (or its 9,10-dihydro derivative) gave the compound 18 (or its 9, 10 -dihydro analogue), which is claimed as a uterotomic and sympatholytic agent. 

Volume loss, venodilation, and arteriolar dilation are likely to result in hypotension with reflex tachycardia. In contrast, hypotension accompanied by bradycardia should suggest intoxication by sympatholytic agents, membrane-depressant drugs, calcium channel blockers, or cardiac glycosides or the presence of hypothermia. 

HYPOTENSION WITH RELATIVE BRADYCARDIA Sympatholytic agents... 

Calcium channel blockers (CCBs) are the most widely used pharmacologic agents for the treatment of peripheral vasospasm (110-112). Sympatholytic agents have also been used in the treatment of Raynaud s phenomenon. Topical nitroglycerin ointment can be applied with a nocturnal nitrate-free interval to avoid nitrate tolerance. 

In addition to the diuretics, which are listed separately, first-line antihypertensive drugs may be grouped into three categories sympatholytic agents ([jS] and [a] blockers. 

Thesis Lipid-mobilizing effects of sympathomimetics are in general related to the degree of their p-tropism the affinities of various catecholamines show, however, notably weaker differences than is the case in various oxedrines. In contradistinction to a-sympathol) cs, the P-sympatholytic agents antagonize the adrenergic lipid mobilization competitively and highly specifically. 

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