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Medicinal chemistry adrenergic agonists

This document defines and classifies sympathomimetic agents. Sympathomimetics mimic endogenous catecholamines of the sympathetic nervous system. They are classified as direct acting, indirect acting, or mixed acting. Direct acting agents directly activate adrenergic receptors. Indirect acting agents enhance endogenous catecholamines. Mixed acting agents have both direct and indirect effects. Examples of each type are provided along with their mechanisms of action and therapeutic uses.

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SYMPATHOMIMETIC AGENTS BY KENCHA SWATHI ASSISTANT PROFESSOR ABIPER BANGALORE
DEFINITION:  Sympathomimetics are substances that mimic or modify the actions of endogenous catecholamines of the sympathetic nervous system. Direct agonists directly activate adrenergic receptors while indirect agonists enhance the actions of endogenous catecholamines.  Sympathomimetics can also be called as adrenergic agonists.  The endogenous catecholamines or sympathetic neurotransmitters are adrenaline, noradrenaline, dopamine.
Classification of sympathomimetics SYMPATHOMIMETICS DIRECT ACTING INDIRECT ACTING MIXED ACTING
DIRECT ACTING SYMPATHOMIMETICS Definition: Drugs which act directly on one or more adrenergic receptors to show its stimulating action .This type of drugs are called as direct acting sympathomimetics. Direct acting sympathomimetics are again classified into three classes: 1.Selective α agonist: Drugs which bind selectively to any one type of α receptors. Eg: methyldopa, clonidine, phenylephrine, naphazoline, oxymetazoline, xylometazoline 2.Selective β agonist: Drugs which bind selectively to any one type of β receptors. Eg: Isoproterenol, Dobutamine, salbutamol, terbutaline, bitolterol 3.Nonselective agonist: Drugs which can bind to both types of receptor(α, β) are called as nonselective adrenergic agonists. Eg: Epinephrine, norepinephrine, Dopamine
STRUCTURE AND ITS USES: METHYL DOPA Uses: 1.selective α2 receptor agonist 2.Antihypertensive agent in pregnancy 3.Relaxes blood vessels for smooth blood flow during hypertension. Side effects:Sedation, drowsiness,drymouth,depression
Clonidine Uses: 1.Preanaesthetic medication 2. Antihypertensive 3. To treat withdrawal symptoms of alcohol,opium,tobacco. 4.Binds to α₂ receptor
PHENYLEPHRINE  Uses: 1. Phenylephrine is an α₁ adrenergic receptor agonist 2.used to treat hypotension, dilate the pupil, and induce local vasoconstriction. (to treat low b.p) 3.To treat nasal decongestion
NAPHAZOLINE  Uses: 1. α-receptor agonist 2. Naphazoline is a decongestant used to relieve redness, puffiness, and itchy/watering eyes due to colds, allergies, or eye irritations.
OXYMETAZOLINE Uses: 1. Oxymetazoline nasal spray is used to relieve nasal discomfort caused by colds, allergies, and hay fever. 2.It is also used to relieve sinus congestion and pressure.
XYLOMETAZOLINE Uses:1.Xylometazoline nasal is a decongestant that shrinks blood vessels in the nasal passages. 2.Dilated blood vessels can cause nasal congestion (stuffy nose). Xylometazoline nasal (for use in the nose) is used to treat stuffy nose caused by allergies, sinus irritation, or the common cold.
ISOPROTERENOL USES: 1. β₁and β₂ specific agonist 2. used as a bronchodilator in asthma. 3. To treat cardiac arrest and AV block
DOBUTAMINE Uses: 1. Dobutamine is used to treat acute but potentially reversible heart failure, such as which occurs during cardiac surgery or in cases of septic or cardiogenic shock, on the basis of its positive inotropic action. 2.Dobutamine can be used in cases of congestive heart failure to increase cardiac output. 3. β₁and β₂ specific agonist
SALBUTAMOL Uses: 1.It is typically used to treat bronchospasm in asthma. 2. To treat chronic obstructive pulmonary disease (COPD) 3. Salbutamol is a β₂ specific agonist
TERBUTALINE Uses: 1.It is typically used to treat bronchospasm in asthma. 2. To treat chronic obstructive pulmonary disease (COPD) 3. Salbutamol is a β₂ specific agonist .
BITOLTEROL Uses: 1.Bronchodilator in chronic lung disorders. 2.withdrawan from the market in 2011 because of severe breathing difficulty in patients after long term use.
EPINEPHRINE Uses: 1.Stimulant in cardiac arrest 2.Vasoconstrictor in shock 3.Bronchodilator 4.Antispasmodic in bronchial asthma
NOREPINEPHRINE Uses: 1.To treat shock 2.To treat cardiac arrest 3. To treat hypotension
DOPAMINE Uses: 1.Neurotransmitter 2. improves the pumping strength of the heart and improves blood flow to the kidneys. 3.Dopamine is used to treat certain conditions that occur when you are in shock, which may be caused by heart attack, trauma, surgery, heart failure, kidney failure, and other serious medical conditions.
INDIRECT ACTING SYMPATHOMIMETICS Definition: Drugs which stimulates the release of endogenous catecholamines/neurotransmitters from the synaptic nerve terminal or storage vesicles are called as indirect acting sympathomimetics. Eg:Hydroxyamphetamine Pseudoephedrine Propylhexedrine
HYDROXYAMPHETAMINE Uses: 1. It releases norepinephrine from post synaptic nerve ending. 2.Diltaes the pupil during eye surgery 3.To treat horner’s pupil syndrome (nerve lesions in eye)
PSEUDOEPHEDRINE Uses: 1.Nasal decongestant 2.For treatment of nasal, sinus, eustachian tube congestion. 3.To treat allergic rhinitis, sinusitis, otitis.
PROPYLHEXEDRINE Uses:Propylhexedrine is used to treat acute nasal congestion related to common cold, allergies and hay fever.
MIXED ACTING SYMPATHOMIMETICS Definition: Drugs which shows both direct action and indirect action are called as mixed acting sympathomimetics. Eg: Ephedrine, Metaraminol
EPHEDRINE Uses: 1.Bronchodilator 2. To treat shortness of breath,chest tightness and wheezing during bronchial asthma. 3. Relieves allergy disorders
METARAMINOL Uses: 1.To treat hypotension 2. To treat cardiac shock 3.Nasal decongestant
Mechanism of action  Direct acting sympathomimetics :Direct acting sympathomimetic drugs directly binds to the adrenergic receptors (α or β) and stimulates the adrenergic agonistic activity.  Indirect acting sympathomimetics: Indirectly acting sympathomimetics may enter into the sympathetic nerve ending and displace stored neurotransmitter into the synaptic cleft. Some of the drugs may inhibit the reuptake of released neurotransmitter into the storage vesicle by using transporter.  Mixed acting sympathomimetics: These drugs directly stimulates the agonistic activity by binding to the adrenergic receptors and indirectly stimulates the receptor by causing the release of stored neurotransmitters from the storage vesicles in the synaptic nerve endings. Both direct and indirect activity has been shown by the mixed acting sympathomimetic drugs.
Medicinal chemistry adrenergic agonists
Medicinal chemistry adrenergic agonists