Sympathomimetic
Sympathomimetic - Related Videos
01:37
Hypothalamic-Pituitary Axis
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2019
The response to stress—be it physical or psychological, acute or chronic—involves activation of the Hypothalamic-Pituitary-Adrenal (HPA) axis. The HPA axis is part of the neuroendocrine system because it involves both neuronal and hormonal communication. Its function is to regulate homeostatic systems—metabolic, cardiovascular, and immune—providing the necessary means to respond to a stressor. What Happens During Stress In response to stress, the neurons in the hypothalamus release...
09:02
Percutaneous Hepatic Perfusion (PHP) with Melphalan as a Treatment for Unresectable Metastases Confined to the Liver
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Cited by 12 •
2016
In this manuscript, we describe percutaneous isolated hepatic perfusion with simultaneous chemofiltration as treatment for unresectable liver metastases. This procedure is performed under general anaesthesia in the angiosuite by an experienced team, consisting of an interventional radiologist, a clinical perfusionist and anaesthesiologist.
FAQs
Direct-acting agents produce effects by stimulating adrenergic alpha or beta receptors themselves, whereas indirect-acting agents increase the availability of endogenous catecholamines such as norepinephrine. This distinction helps explain why two drugs in the same broad class may produce different physiological responses. The mechanism influences whether treatment primarily affects vascular tone, cardiac activity, airway caliber, or several systems together.
Receptor selectivity helps determine which physiological response is emphasized. Alpha-receptor stimulation can produce vasoconstriction, while beta-receptor stimulation may increase heart rate or promote bronchodilation. Because sympathomimetics can affect more than one organ system, clinicians consider the desired effect and the possibility of unwanted cardiovascular or neurologic responses when selecting an agent.
Dose can change the balance and intensity of sympathomimetic effects. Depending on receptor selectivity and dose, treatment may influence vascular constriction, cardiac rate, airway opening, or nasal congestion. This relationship makes dose an important clinical variable rather than a simple measure of strength. Monitoring helps clinicians assess whether the intended response is occurring without excessive cardiovascular or neurologic effects.
Cardiovascular and neurologic effects require particular attention because sympathomimetic activity can influence heart rate, vascular tone, and other physiological functions. The relevant risk depends on the agent's receptor selectivity, mechanism, and dose. Clinical monitoring is therefore important when these drugs are used, especially when treatment is intended to produce a strong cardiovascular or respiratory response.
Clinical uses include managing hypotension and allergic reactions, where altering sympathetic activity may support cardiovascular function or other physiological responses. The appropriate effect depends on the drug's adrenergic receptor activity and whether it acts directly or indirectly. Because these treatments can also affect heart rate, vascular tone, and neurologic function, clinicians monitor the patient while addressing the immediate indication.
These drugs may be used in asthma to promote bronchodilation and in nasal congestion to reduce congestion through vasoconstriction. Although both applications involve the respiratory or upper-airway system, they depend on different physiological outcomes. Receptor selectivity and dose help shape the response, while clinical observation remains important because systemic cardiovascular or neurologic effects can accompany treatment.