PNS
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Questions and Answers

Which of the following are cholinergic drugs? (Select all that apply)

  • Mirabegron
  • Bethanechol (correct)
  • Pilocarpine (correct)
  • Atropine

    • Cholinergic drugs can have adverse effects such as diarrhea and increased salivation.

    True

    What is the primary use of Cevimeline?

    Treats dry mouth in Sjogren's syndrome

    Atropine causes ______ receptor blockade.

    <p>muscarinic</p> Signup and view all the answers

    What condition is treated with Pyridostigmine?

    <p>Myasthenia gravis</p> Signup and view all the answers

    Which of these are side effects of Oxybutynin? (Select all that apply)

    <p>Urinary retention</p> Signup and view all the answers

    Irreversible cholinesterase inhibitors are primarily used as insecticides.

    <p>True</p> Signup and view all the answers

    Match the following drugs to their primary effects:

    <p>Bethanechol = Urinary retention treatment Cevimeline = Dry mouth treatment Pilocarpine = Glaucoma treatment Atropine = Muscarinic blockade</p> Signup and view all the answers

    What is the treatment for muscarinic poisoning?

    <p>Atropine and supportive therapy</p> Signup and view all the answers

    The main condition treated by neostigmine is ______.

    <p>Myasthenia gravis</p> Signup and view all the answers

    Which of the following drugs are considered catecholamines?

    <p>Norepinephrine</p> Signup and view all the answers

    Adrenergic agonists can be administered orally.

    <p>False</p> Signup and view all the answers

    What is the therapeutic use of Alpha 1 adrenergic agonists?

    <p>Hemostasis</p> Signup and view all the answers

    Epinephrine acts on all ___ adrenergic receptor subtypes.

    <p>four</p> Signup and view all the answers

    Which drug is a selective Beta 1 agonist used for heart failure?

    <p>Dobutamine</p> Signup and view all the answers

    What are the main adverse effects of Beta 2 agonists?

    <p>Hyperglycemia, tremors</p> Signup and view all the answers

    What is the primary use of Norepinephrine?

    <p>Shock</p> Signup and view all the answers

    What should not be combined with Dobutamine?

    <p>MAOIs</p> Signup and view all the answers

    Which of the following are adverse effects of Alpha 1 antagonists?

    <p>Orthostatic hypotension</p> Signup and view all the answers

    Beta blockers can help with hyperthyroid conditions.

    <p>True</p> Signup and view all the answers

    Clonidine is an indirect-acting anti-adrenergic agent used for ___ and ___ .

    <p>HTN, pain</p> Signup and view all the answers

    Study Notes

    Cholinergic Agonists/Antagonists

    Cholinergic Drugs

    • Mimic or block acetylcholine
    • Contraindications:
      • Lactating females: decrease milk production due to anticholinergic side effects
      • Elderly: not recommended

    Bethanechol

    • Parasympathomimetic agent
    • Selective agonist: muscarinic cholinergic receptor
    • Binds reversibly to muscarinic cholinergic receptors, causing activation
    • Uses:
      • Urinary retention
      • Investigational GI uses
      • Off-label use for GI reflux
    • Adverse effects:
      • Hypotension
      • Cramps from increased tone and motility of GI
      • Diarrhea
      • Increased salivation
      • Asthma exacerbation
      • Dysrhythmias in hyperthyroidism
    • Contraindications:
      • Hyperthyroid patients

    Cevimeline

    • Treats dry mouth in Sjogren's syndrome
    • Derivative of acetylcholine

    Pilocarpine

    • Topical therapy for glaucoma
    • Treats dry mouth from Sjogren's syndrome

    Acetylcholine

    • Rapid miosis after delivery in cataract surgery

    Structure of Cholinergic Drugs

    • Except for pilocarpine, they are quaternary ammonium compounds, always carrying a positive charge, and don't cross membranes easily

    Muscarinic Poisoning

    • Caused by ingestion of certain mushrooms or direct-acting muscarinic agonists, and cholinesterase inhibitors
    • Symptoms:
      • Profuse salivation
      • Lacrimation
      • Visual disturbances
      • Bronchospasm
      • Diarrhea
      • Bradycardia
      • Hypotension with possible cardiac collapse
    • Treatment:
      • Atropine and supportive therapy

    Atropine

    • Causes muscarinic receptor blockade
    • Uses:
      • Pre-anesthetic
      • Disorders of the eye
      • Bradycardia
      • Intestinal hypertonicity/motility
      • Muscarinic agonist poisoning
      • PUD
      • Asthma
      • Biliary colic
    • Adverse effects:
      • Dry mouth
      • Blurred vision
      • Photophobia
      • Elevation of intraocular pressure
      • Urinary retention
      • Constipation
      • Anhidrosis
      • Tachycardia
      • Asthma
    • Contraindications:
      • Avoid combining with other drugs capable of causing muscarinic blockade

    Anti-Cholinergic Drugs for Overactive Bladder

    • Oxybutynin:
      • Acts primarily at the M3 receptor
      • Available in short-acting and long-acting forms
      • Adverse effects:
        • Dry mouth
        • Constipation
        • Tachycardia
        • Urinary hesitancy/retention
        • Mydriasis
        • Blurred vision
        • Dry eyes
        • Hallucination/agitation in pediatrics and geriatrics
    • Darfenacin:
      • Treats overactive bladder
      • Adverse effects:
        • Dry mouth
        • Constipation
    • Solfenacin:
      • Adverse effects:
        • Dry mouth
        • Blurred vision
        • High doses can cause prolongation of QT interval
    • Tolterodine:
      • Can prolong QT interval
      • Adverse effects:
        • Dry mouth
        • Constipation
    • Fesoterodine:
      • Adverse effects:
        • Dry mouth
        • Constipation
    • Trospium:
      • Adverse effects:
        • Dry mouth
        • Constipation
    • Mirabegron:
      • MOA: relaxation during filling and increased bladder capacity, decreases frequency
      • Adverse effects:
        • Dry mouth
        • Constipation
        • Can prolong QT and increase BP
    • Vibegron:
      • Adverse effects:
        • Dry mouth
        • Constipation
    • Botox (onabotulinumtoxina):
      • MOA: injected in detrusor muscle, inhibits calcium-dependent release of acetylcholine
      • Adverse effects:
        • Voiding dysfunction
        • UTIs

    SNRIs

    • Duloxetine:
      • Cannot be given with MAOIs and is metabolized by CYP
    • Venlafaxine and Duloxetine:
      • Non-traditional therapy
      • Facilitates urine storage, augments PNS innervation, and inhibits sympathetic innervation

    Other Muscarinic Antagonists (Anti-Cholinergic)

    • Scopolamine:
      • Similar to atropine
      • Uses:
        • Suppresses emesis and motion sickness
        • Cycloplegia/mydriasis for eye symptoms
        • Pre-anesthetic sedation/obstetric amnesia
    • Ipratropium bromide:
      • Uses:
        • Asthma
        • COPD
        • Rhinitis from allergies or common cold
    • Antisecretory anticholinergics:
      • Reduce salivation
      • Glycopyrrolate, Mepenzolate, Methscopolamine, and Propantheline
    • Dicyclomine:
      • Treats IBS, diarrhea, or hyper-motility
    • Mydriatic-cycloplegics:
      • Produce mydriasis and cycloplegia for eye procedures
      • Atropine, homatropine, scopolamine, cyclopentolate, and tropicamide
    • Centrally acting anticholinergics:
      • Treats Parkinson's
      • Benztropine and trihexyphenidyl

    Anti-Muscarinic Poisoning

    • Caused by natural products or selective anti-muscarinic drugs
    • Symptoms:
      • Dry mouth
      • Blurred vision
      • Photophobia
      • Hyperthermia
      • CNS effects
      • Hot, dry/flush skin
      • Death from respiratory depression
    • Treatment:
      • Physostigmine (inhibitor of acetylcholinesterase)

    Cholinesterase Inhibitors

    • Prevent degradation of acetylcholine by acetylcholinesterase, increasing levels of acetylcholine and enhancing cholinergic transmission

    Reversible Cholinesterase Inhibitors

    • Pyridostigmine:
      • Does not cross membranes readily, absorbed poorly with oral administration, minimal effects on the brain and fetus
      • Used for myasthenia gravis
      • MOA: decreases breakdown of acetylcholine
      • Adverse effects:
        • Excessive muscarinic stimulation
        • Neuromuscular blockade
      • Precautions/contra:
        • Obstruction of GI or urinary tract
        • PUD
        • Asthma
        • Coronary insufficiency
        • Hyperthyroidism

    Irreversible Cholinesterase Inhibitors

    • Highly toxic, primarily used as insecticides
    • Only clinical indication: glaucoma
    • Lipid soluble
    • Poisoning: excessive muscarinic stimulation and depolarizing neuromuscular blockade, known as "cholinergic crisis"
    • Treatment:
      • Atropine
      • Respiratory support

    Myasthenia Gravis

    • Fluctuating muscle weakness and predisposition to rapid fatigue
    • Symptoms:
      • Ptosis
      • Dysphasia
      • Weakness
    • Autoimmune process where antibodies attack the nicotinic M receptors on skeletal muscle
    • Treatment:
      • Reversible cholinesterase inhibitors by preventing inactivation, anticholinesterase agents can intensify the effects of acetylcholine increasing muscle strength
      • Atropine to suppress muscarinic responses if excessive
    • Signs of improvement: ease of swallowing, ability to raise eyelids
    • Overmedication: excessive salivation and other muscarinic responses

    Adrenergic Agonists

    • Referred to as sympathomimetics, with two classes: catecholamines and non-catecholamines
    • Catecholamines:
      • Contain a catechol group and amine group
      • Metabolized by enzymes MAO and catechol-O-methyltransferase (COMT)
      • Cannot be administered orally, have a brief duration of action, and cannot cross the blood-brain barrier (BBB)
      • Examples: epinephrine, norepinephrine, isoproterenol, dopamine, and dobutamine
    • Non-catecholamines:
      • Do not contain a catechol group
      • Not substrates for COMT, and metabolized slowly by MAO
      • Have longer half-lives and can be given orally
      • Can cross the BBB
    • Receptor specificity:
      • Albuterol: B2 at low doses, B1 and B2 at high doses
      • Isoproterenol: B1 and B2
      • Epinephrine: acts on all 4 adrenergic receptor subtypes (A and B)
      • Selectivity is relative and depends on the dose
    • Adrenergic agonist drugs:
      • Epinephrine:
        • Uses: delaying absorption of local anesthetics, control of superficial bleeding, increase in blood pressure, and mydriasis
        • Adverse effects (AE): hypertension crisis, dysrhythmias, angina, and necrosis following extravasation
      • Norepinephrine:
        • Uses: hypotensive states and cardiac arrest
        • AE: tachydysth, angina, hypertension, and local necrosis
      • Isoproterenol:
        • Uses: AV block, cardiac arrest, and increase in cardiac output
        • AE: tachyarrhythmias, angina, and hyperglycemia in diabetes
      • Dopamine:
        • Uses: shock and heart failure
        • AE: tachy, dysrhythmias, anginal pain
      • Dobutamine:
        • Uses: heart failure
        • AE: tachy
      • Phenylephrine:
        • Uses: locally to reduce nasal congestion, and parenterally to increase blood pressure
        • AE: hypertension, necrosis of tissue, and bradycardia
      • Albuterol:
        • Uses: asthma through bronchodilation
        • AE: tremor and tachy
      • Ephedrine:
        • Uses: asthma, shock, and anesthesia-induced hypotension
        • AE: hypertension, dysrhythmias, angina, and hyperglycemia in diabetes

    Adrenergic Antagonists

    • All adrenergic antagonists produce reversible competitive blockade
    • More selective than agonists, with alpha and beta antagonists blocking specific groups
    • Alpha blocking agent:
      • Uses: hypertension, reversal of toxicity from alpha agonist, benign prostatic hyperplasia (BPH), pheochromocytoma, and Raynaud disease
      • AE: orthostatic hypotension, reflex tachycardia, nasal congestion, inhibition of ejaculation, and nausea retention
    • Alpha 1 blocking agent:
      • Prazosin, doxazosin, tamsulosin, alfuzosin, and silodosin
      • Uses: hypertension, BPH, and pheochromocytoma
      • AE: postural hypotension, abnormal ejaculation, and increased risk of rhinitis
    • Alpha 2 blocking agent:
      • Phentolamine and phenoxybenzamine
      • Uses: pheochromocytoma, prevention of tissue necrosis, and reversal of soft tissue anesthesia
    • Beta blocking agent:
      • Uses: anti-anginal therapy, hypertension, dysrhythmias, myocardial infarction, heart failure, hyperthyroidism, migraine, pheochromocytoma, and stage fright
      • AE: bradycardia, bronchoconstriction in asthma patients, and hypoglycemia in diabetes
    • Beta blocking agent:
      • Propranolol, metoprolol, labetalol, carvedilol, and esmolol
      • Uses: hypertension, angina, dysrhythmias, and myocardial infarction
      • AE: bradycardia, bronchoconstriction, and hypoglycemia in diabetes

    Indirect-Acting Anti-Adrenergic Agents

    • Clonidine:
      • Indication: hypertension, pain, and ADHD
      • A2 adrenergic agonist that causes selective activation of A2 receptors in the CNS
      • Causes bradycardia and decreased cardiac output
      • Lipid soluble
      • AE: drowsiness, xerostomia, rebound hypertension with withdrawal, constipation, impotence, gynecomastia, and adverse CNS effects
    • Guanfacine:
      • Same as clonidine
    • Methyldopa:
      • Oral antihypertensive that acts on CNS sites
      • AE: hemolytic anemia and hepatic necrosis
      • Great for pregnancy
    • Methyldopate:
      • IV antihypertensive
      • AE: positive Coombs test, hemolytic anemia, hepatic toxicity, xerostomia, sexual dysfunction, orthostatic hypotension, and CNS effects

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    Description

    This quiz covers cholinergic drugs, including their effects, uses, and contraindications. It also discusses specific drugs such as Bethanechol and their administration.

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