sympathomimetic drugs


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sympathomimetic drugs

agents that mimic the sympathetic nervous system, acting at alpha- or beta-adrenergic receptors within target tissues; vasoconstrictor sympathomimetics raise blood pressure by acting on alpha-adrenergic receptors, causing central vasoconstriction; beta receptor-active sympathomimetics dilate bronchi and peripheral blood vessels; beta-blockers block beta-receptor sites and promote peripheral vasoconstriction; adrenaline is a sympathomimetic drug that acts on both alpha- and beta-adrenergic receptors and is used to counter symptoms of anaphylaxis (it both raises blood pressure and dilates bronchi) Table 1
Table 1: Effects of stimulation of alpha, beta and dopamine receptors
ReceptorActionStimulating drug
Alpha-1 (α1); postsynapticVasoconstriction; positive inotropism; antidiuresisAdrenaline +
Noradrenaline +++
Alpha-2 (α2); presynapticVasodilatation; inhibition of noradrenaline releaseAdrenaline +
Noradrenaline +++
Dopamine +
Alpha-2 (α2); postsynapticConstriction of coronary arteries; promotion of salt and water excretionAdrenaline +
Noradrenaline +++
Dopamine +
Beta-1 (β1); postsynapticPositive inotropism; chronotropism; renin releaseAdrenaline ++
Noradrenaline ++
Isoprenaline ++
Dopamine +
Beta-2 (β2); presynapticNoradrenaline release accelerated; positive inotropism; chronotropismAdrenaline +
Isoprenaline +++
Beta-2 (β2); postsynapticVasodilatation; relaxation of bronchial smooth muscleAdrenaline +
Isoprenaline +++
Dopamine1; postsynapticVasodilatation; diuresisDopamine ++
Dopamine1; presynapticInhibits noradrenaline releaseDopamine +

Plus signs indicate degree of effect.

sympathomimetic drugs 

Drugs that produce an effect similar to that obtained by stimulation of the sympathetic nervous system. Some of these predominantly act on the adrenergic alpha-receptors (e.g. noradrenaline (norepinephrine)), while others act on the adrenergic beta-receptors (e.g. isoproterenol). Others have little direct effect on the adrenergic receptors but enhance the release of natural catecholamine from the sympathetic nerve terminals (e.g. amphetamine, phenylpropanolamine). Sympathomimetic drugs are used (1) in the treatment of open-angle glaucoma by decreasing aqueous humour secretion and increase the outflow through the trabecular meshwork thus reducing the intraocular pressure (e.g. adrenaline (epinephrine), apraclonidine, dipivefrine hydrochloride, brimonidine tartrate), (2) dilate the pupil without affecting accommodation (e.g. phenylephrine) and (3) constrict conjunctival blood vessels (e.g. naphazoline, tetrahydrozoline). Syn. adrenergic agonist; adrenergic stimulating agent. See alpha-adrenergic agonist; mydriatic.
References in periodicals archive ?
Clinically significant cardiovascular effects and fatalities have been reported in association with excessive use of inhaled sympathomimetic drugs.
Other sympathomimetic drugs used for weight loss have been associated with serious cardiovascular reactions.
Summary: TEHRAN (FNA)- Researchers at Payam-e-Noor University of Tehran in collaboration with experts from Tabriz University of Medical Sciences found a simple synthesis method for zinc oxide (and hydroxide) and their application in modified carbon paste electrodes for determination of sympathomimetic drugs at micro-molar scales.
Sympathomimetic drugs, including cocaine and amphetamines, are commonly associated with intracranial hemorrhage, possibly due to transient hypertension or arteritis-like vascular change.
Dental professionals should use caution when administering other sympathomimetic drugs (e.
Amphetamines are non-catecholamine indirect sympathomimetic drugs that structurally resemble noradrenaline (2).
The differential diagnosis of the serotonin syndrome in turn includes malignant neuroleptic syndrome (MNS), MAOI overdose, tyramine reaction, strychnine ingestion, and the use of cocaine, amphetamines or other sympathomimetic drugs.
He recommended the warning include that sympathomimetic drugs of this type have been associated with increases in blood pressure and heart rate, which can result in myocardial infarction, stroke, and sudden death, and the precise risk associated with the ADHD drugs is uncertain.
The warning should include the points that sympathomimetic drugs of this type have been associated with increases in blood pressure and heart rate, which can result in myocardial infarction, stroke, and sudden death, and that the precise risk associated with the ADHD drugs is uncertain, he recommended.
Arousal and stability: The effects of five new sympathomimetic drugs suggest a new principle for the prevention of space motion sickness.
Unlike sympathomimetic drugs and ephedrine, however, green tea extracts have not been shown to increase heart rate and are not associated with adverse cardiovascular effects.
Ephedrine and other sympathomimetic drugs (eg, cocaine, methamphetamine) are derived from phenylethylamine.