What is the Difference Between Sympathomimetic and Sympatholytic Drugs
The key difference between sympathomimetic and sympatholytic drugs is that sympathomimetic drugs are drugs that can enhance adrenergic function, whereas sympatholytic drugs are drugs that can interrupt adrenergic function.
The term adrenergic refers to the interaction between proteins and drugs with adrenaline or noradrenaline, respectively. Adrenergic drugs are medications that can stimulate the nerves in our body’s sympathetic nervous system.
CONTENTS
1. Overview and Key Difference
2. What is Sympathomimetic Drug
3. What is Sympatholytic Drug
4. Sympathomimetic vs Sympatholytic Drug in Tabular Form
5. Summary – Sympathomimetic vs Sympatholytic Drug
What is Sympathomimetic Drug?
Sympathomimetic drugs are a type of adrenergic drug that is used as a stimulant compound showing effects of endogenous agonists of the sympathetic nervous system. These drugs are also known as adrenergic drugs or adrenergic amines. These drugs are important in treating cardiac arrest and low blood pressure. They can also treat delay premature labour conditions.
Moreover, there are several mechanisms through which these drugs can act. Some of these mechanisms include direct activation of postsynaptic receptors, blocking, breaking down and re-up taking of certain neurotransmitters, and stimulation of production and release of catecholamines. Among these mechanisms, direct-acting occurs through alpha-adrenergic agonists, beta-adrenergic agonists, and dopaminergic agonists. The indirect action occurs through MAOIs, COMT inhibitors, release of stimulants, etc.
Some examples of sympathomimetic drugs include amphetamine, benzylpiperazine, cathine, cathinone, cocaine, ephedrine, maprotiline, MDMA, and methcathinone.
What is Sympatholytic Drug?
Sympatholytic drugs are a type of adrenergic drugs that can oppose the downstream effects of postganglionic nerve firing. These nerve firings occur in effector organs that are innervated by the sympathetic nervous system. Moreover, these drugs can be used as antihypertensives, as medication to treat anxiety, including generalized anxiety disorder and panic disorder.
When considering the mechanism of action, these drugs can inhibit the signals of epinephrine and norepinephrine, inhibit the adrenergic receptor signalling through blocking the synthesis of catecholamines, by inhibiting VMAT, and being toxic to sympathetic neurons, etc.
The uses of this drug include ganglion blocking, periphery acting, centrally acting, treating anxiety by acting as beta-blockers, etc. Sympatholytic drugs are also known as sympathoplegic drugs.
What is the Difference Between Sympathomimetic and Sympatholytic Drugs?
Adrenergic drugs are medications that can stimulate the nerves in the body’s sympathetic nervous system. The key difference between sympathomimetic and sympatholytic drugs is that sympathomimetic drugs are drugs that can enhance adrenergic function, whereas sympatholytic drugs are drugs that can interrupt adrenergic function. Amphetamine, benzylpiperazine, cathine, cathinone, cocaine, ephedrine, maprotiline, MDMA, and methcathinone are some examples of sympathomimetic drugs, whereas prazosin, rescinnamine, reserpine, rilmenidine, mecamylamine, trimethaphan, and guanethidine are some examples of sympatholytic drugs.
Moreover, the sympathomimetic drugs act by direct activation of postsynaptic receptors, blocking, breaking down and re-up taking of certain neurotransmitters, and stimulation of production and release of catecholamines. Meanwhile, sympatholytic drugs act via the inhibition of the signals of epinephrine and norepinephrine, inhibition of adrenergic receptor signaling through blocking the synthesis of catecholamines, by inhibition of VMAT, by being toxic to sympathetic neurons, etc.
The following infographic lists the differences between sympathomimetic and sympatholytic drugs in tabular form for side by side comparison
Summary – Sympathomimetic vs Sympatholytic Drugs
Adrenergic drugs are medications that can stimulate the nerves in the body’s sympathetic nervous system. The key difference between sympathomimetic and sympatholytic drugs is that sympathomimetic drugs are drugs that can enhance adrenergic function, whereas sympatholytic drugs are drugs that can interrupt adrenergic function.
Reference:
1. Cafasso, Jacquelyn. “Adrenergic Drugs: Types, Uses, and Effects.” Healthline, Healthline Media, 28 Aug. 2018.
Image Courtesy:
1. “Blausen 0838 Sympathetic Innervation” Blausen.com staff (2014). "Medical gallery of Blausen Medical 2014". WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. – Own work (CC BY 3.0) via Commons Wikimedia
2. “Tablets pills medicine medical waste” By Pöllö – Own work (CC BY 3.0) via Commons Wikimedia
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