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(Part 1: Autonomic Nervous System Drugs) - Coggle Diagram
Part 1: Autonomic Nervous System Drugs
Cholinergic System
Cholinergic Agonists
Direct Muscarinic Receptor Agonists
Pilocarpine
Cevimeline
Bethanechol
Carbachol :
Methacholine
Acetylcholine
Muscarine
Arecoline
Oxotremorine
Indirect Cholinergic Agonists (Anticholinesterases)
Reversible Carbamates
Neostigmine
Physostigmine
Pyridostigmine
Rivastigmine
Donepezil
Galantamine
Organophosphates (Irreversible)
Echothiopate
Parathion
Acetylcholinesterase Reactivators
Pralidoxime
Obidoxime
Trimedoxime
Cholinergic Antagonists
Muscarinic Receptor Antagonists
Non-Selective
Atropine
Scopolamine
Homatropine
Tropicamide
M1 Selective
Pirenzepine
Telenzepine
M3 Selective
Darifenacin
Solifenacin
M2/M3 Mixed
Ipratropium
Tiotropium
Umeclidinium
Glycopyrrolate
Antispasmodics (GI)
Dicyclomine
Hyoscyamine
Nicotinic Receptor Antagonists
Ganglionic Blockers (Nn)
Mecamylamine
Trimethaphan
Neuromuscular Blockers (Nm)
Non-depolarizing
Tubocurarine
Atracurium
Cisatracurium
Vecuronium
Rocuronium
Pancuronium
Depolarizing
Succinylcholine (Suxamethonium)
Adrenergic System
Adrenergic Agonists (Sympathomimetics)
Direct
Direct Alpha-1 Agonists
Methoxamine
Class: α1-agonist (pure)
MOA: Potent vasoconstriction → ↑ BP (reflex bradycardia)
Use: Supraventricular tachycardia (SVT), hypotension during anesthesia
Dose: 5–10 mg slow IV
Exam Pearl: دواء مش مشهور يرفع الضغط ويبطئ القلب (Uncommon drug that raises BP and slows HR)
Midodrine
Class: α1-agonist
MOA: Peripheral vasoconstriction → ↑ BP
Use: Orthostatic hypotension
Dose: 2.5–10 mg TID (avoid before sleep)
Key AE: Supine hypertension
Phenylephrine
MOA: Peripheral vasoconstriction → ↑ BP
Use: Nasal congestion (decongestant), hypotension
Dose: PO 10 mg q4h; Nasal spray 0.25–1%
Key AE: Hypertension, rebound congestion
Class: α1-agonist
Direct Alpha-2 Agonists
Clonidine
MOA:
↓ Sympathetic outflow from CNS → ↓ BP and ↓ HR
Use:Hypertension, ADHD, opioid withdrawal
Dose:0.1–0.3 mg PO BID (or weekly transdermal patch)
Key AE:Sedation, rebound hypertension if abruptly stopped
Sudden discontinuation → severe rebound hypertension
Dexmedetomidine
MOA:Central α₂ stimulation → ↓ sympathetic activity → sedation and analgesia
Use:Sedation in ICU or procedural sedation
Dose:0.2–0.7 mcg/kg/hr IV infusion
Exam Pearl:Sedation with minimal respiratory depression
Guanfacine
MOA:↓ Sympathetic outflow from CNS → ↓ BP
Use:ADHD, hypertension
Dose:1–4 mg PO daily (ER form commonly for ADHD)
Methyldopa
MOA:Converted to α-methylnorepinephrine in CNS → ↓ sympathetic tone → ↓ BP
Use:Hypertension in pregnancy
Dose:250–500 mg PO BID–TID
Key AE:Coombs-positive hemolytic anemia
Direct Beta-1 Agonists
Dobutamine
MOA:β₁ stimulation → ↑ cardiac contractility → ↑ cardiac output
Use:Acute heart failure, cardiogenic shock
Dose:2–20 mcg/kg/min IV infusion
Exam Pearl:Strong inotrope used to increase cardiac output in cardiogenic shock
Direct Beta-2 Agonists
Short-acting (SABA)
Albuterol
MOA:Stimulates β2 receptors → bronchodilation
Main Clinical Use:
First-line rescue inhaler for acute asthma
Dose:2 puffs (90 mcg/puff) every 4–6 h PRN
Terbutaline
MOA:β₂ stimulation → bronchial smooth muscle relaxation
Use:Acute asthma exacerbation
Dose:Asthma: 0.25 mg 5mg
Key AE:Tachycardia, tremor, hypokalemia
Fenoterol
Asthma and COPD bronchospasm relief
Dose:Inhalation: 100–200 mcg per dose PRN
Key AE:Tachycardia, tremor, hypokalemia
Exam Pearl:Short-acting β₂ agonist (SABA) used for rapid bronchodilation
Long-acting (LABA)
Salmeterol
Class:Long-acting β2-agonist (LABA)
MOA:Stimulates β2 receptors → long bronchodilation (~12 h)
Main Clinical Use:Asthma/COPD maintenance (always with ICS in asthma)
Typical Adult Dose:50 mcg inhalation BID
Key Adverse Effect:Tachycardia, tremor
Exam Pearl:Not used for acute asthma attacks (slow onset).
Formoterol
Class:Long-acting β2-agonist (LABA)
MOA:Stimulates β2 receptors → bronchodilation
Main Clinical Use:Asthma & COPD maintenance (with ICS in asthma)
Typical Adult Dose:12 mcg inhalation BID
Key Adverse Effect:Tremor, tachycardia
Exam Pearl:Faster onset than salmeterol → can be used in ICS-formoterol reliever regimens.
Mixed Alpha/Beta Agonists
Epinephrine
Class:α1, β1, β2 adrenergic agonist
MOA:↑ HR & contractility (β1) + bronchodilation (β2) + vasoconstriction (α1)
Main Clinical Use:Anaphylaxis
Typical Adult Dose:0.3–0.5 mg IM (1 mg/mL)
Key Adverse Effect:Tachycardia / hypertension
Exam Pearl:Drug of choice for anaphylaxis.
Norepinephrine
Class:α1, α2, β1 adrenergic agonist (vasopressor)
MOA:α1 vasoconstriction → ↑ SVR and ↑ BP
Main Clinical Use:First-line vasopressor in septic shock
Typical Adult Dose:0.05–0.5 mcg/kg/min IV infusion (titrate)
Key Adverse Effect:Ischemia / extravasation necrosis
Exam Pearl:Preferred over dopamine in septic shock due to lower arrhythmia risk
Dopamine
Class:Dose-dependent adrenergic agonist (D1, β1, α1)
MOA:Low dose D1 → renal vasodilation; moderate β1 → ↑ CO; high α1 → vasoconstriction
Main Clinical Use:Shock with hypotension + bradycardia
Typical Adult Dose:2–20 mcg/kg/min IV infusion
Key Adverse Effect:Tachyarrhythmias
Exam Pearl:Not first-line in septic shock due to higher arrhythmia risk vs norepinephrine.
Indirect Agonists (Releasing Agents)
Amphetamine
Class:Indirect sympathomimetic stimulant
MOA:↑ release of norepinephrine & dopamine
Main Clinical Use:ADHD, narcolepsy
Typical Adult Dose:5–40 mg/day PO (divided)
Key Adverse Effect:Hypertension, insomnia
Exam Pearl:Increases NE/DA release → CNS stimulation.
Methamphetamine
Class:Potent CNS stimulant (amphetamine derivative)
MOA:Massive ↑ dopamine, norepinephrine release
Main Clinical Use:ADHD (rarely used medically)
Typical Adult Dose:5 mg once or twice daily PO
Key Adverse Effect:High addiction potential
Exam Pearl:Stronger CNS stimulant than amphetamine.
Ephedrine
Class:Mixed-acting sympathomimetic
MOA:Direct α & β stimulation + ↑ norepinephrine release
Main Clinical Use:Hypotension (especially during anesthesia)
Typical Adult Dose:5–10 mg IV bolus
Key Adverse Effect:Tachycardia, hypertension
Exam Pearl:Mixed mechanism: direct receptor stimulation + NE release
Adrenergic Antagonists (Sympatholytics
Alpha Blockers
Alpha-1 Selective
Prazosin
Doxazosin
Terazosin
Tamsulosin
Silodosin
Non-Selective Alpha Blockers
Phenoxybenzamine
Phentolamine
Alpha-2 Blockers
Yohimbine
Beta Blockers
Non-Selective (β1=β2)
Propranolol
Nadolol
Timolol
Pindolol
Sotalol
Cardioselective (β1>β2)
Metoprolol
Atenolol
Bisoprolol
Esmolol
Nebivolol
Mixed Alpha/Beta Blockers (مكرر لكن نضعه هنا أيضاً)
Labetalol
Carvedilol
Beta Blockers with ISA
Acebutolol
Carteolol
Penbutolol
Pindolol
Mixed Alpha/Beta Blockers
Labetalol
Carvedilol