chapter 14 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Chapter 14 PowerPoint Presentation
Download Presentation
Chapter 14

Loading in 2 Seconds...

play fullscreen
1 / 32

Chapter 14 - PowerPoint PPT Presentation


  • 205 Views
  • Uploaded on

Chapter 14. Muscarinic Agonists and Antagonists. Cholinergic Drugs. Agents that influence the activity of cholinergic receptors Most mimic or block the actions of acetylcholine. Cholinesterase inhibitors Indirectly prevent the breakdown of acetylcholine. Cholinergic Drugs.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Chapter 14' - deliz


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
chapter 14

Chapter 14

Muscarinic Agonists and Antagonists

cholinergic drugs
Cholinergic Drugs
  • Agents that influence the activity of cholinergic receptors
  • Most mimic or block the actions of acetylcholine.
  • Cholinesterase inhibitors
    • Indirectly prevent the breakdown of acetylcholine
cholinergic drugs1
Cholinergic Drugs
  • Toxicology encompasses
    • Nicotine
    • Insecticides
    • Chemical warfare
tips for understanding the cholinergic drugs
Tips for Understanding the Cholinergic Drugs
  • Know the receptors that the drug affects.
  • Know the normal responses to activation of those receptors.
  • Know whether the drug in question increases or decreases receptor activation.
muscarinic agonists and antagonists
Muscarinic Agonists and Antagonists
  • Muscarinic agonists
    • Bethanechol
    • Other muscarinic agonists
    • Toxicology of muscarinic agonists
  • Muscarinic antagonists (anticholinergic drugs)
    • Atropine
    • Anticholinergic drugs for overactive bladder (urge incontinence)
    • Other muscarinic antagonists
    • Toxicology of muscarinic antagonists
tips for understanding the cholinergic drugs1
Tips for Understanding the Cholinergic Drugs
  • Bethanechol (prototype drug)
    • Selective agonist at muscarinic cholinergic receptors
    • Refer to Table 14-2.
    • Note the effects muscarinic receptors can produce.
    • Bethanechol activates muscarinic receptors (agonist).
    • Know which receptors a drug interacts with (Table 14-2) and what those receptors do (Table 14-2).
    • You can predict the types of responses you might expect from bethanechol.
muscarinic agonists and antagonists1
Muscarinic Agonists and Antagonists
  • Muscarinic agonists
    • Bethanechol
    • Other muscarinic agonists
    • Toxicology of muscarinic agonists
muscarinic agonists and antagonists2
Muscarinic Agonists and Antagonists
  • Principal structures affected by muscarinic activation
    • Heart: bradycardia
    • Exocrine glands: increase sweating, salivation, bronchial secretions, and secretion of gastric acid
    • Smooth muscles
      • Contraction in lung (constriction)
      • GI tract (increased tone/motility)
      • Bladder (contraction of detrusor)
      • Vascular (relaxation, vasodilation, hypotension)
      • Eye (pupillary constriction and ciliary contraction)
muscarinic agonists
Muscarinic Agonists
  • Bethanechol
    • Mechanism of action
  • Pharmacologic effects
    • Pharmacokinetics
  • Therapeutic uses
    • Urinary retention
    • Gastrointestinal uses
muscarinic agonists1
Muscarinic Agonists
  • Adverse effects
    • Cardiovascular system
    • Alimentary system
    • Urinary tract
    • Exacerbation of asthma
    • Dysrhythmias in hyperthyroid patients
  • Preparations, dosage, and administration
other muscarinic agonists
Other Muscarinic Agonists
  • Cevimeline
    • Actions and uses
    • Adverse effects
    • Drug interactions
    • Preparations, dosage, and administration
other muscarinic agonists1
Other Muscarinic Agonists
  • Pilocarpine
    • Glaucoma
  • Acetylcholine
    • Miosis
  • Muscarine
    • Present in poisonous mushrooms
overactive bladder
Overactive Bladder
  • Also known as urgency incontinence, detrusor instability, and sometimes “can’t-hold-it-anymore” incontinence
  • Four major symptoms: urinary urgency, urinary frequency, nocturia, and urge incontinence
  • Urge incontinence often results from involuntary contractions of the bladder detrusor.
overactive bladder1
Overactive Bladder
  • Affects up to one-third of Americans
  • Can develop at any age, but is most predominant in elderly patients
  • Two modes of treatment: behavioral therapy and drug therapy
  • If ineffective—percutaneous tibial nerve stimulation (PTNS) may be tried.
muscarinic antagonists anticholinergic drugs
Muscarinic Antagonists(Anticholinergic Drugs)
  • Competitively block the actions of acetylcholine at muscarinic receptors
  • Most muscarinic receptors on structures innervated by parasympathetic nerves
  • Also known as parasympatholytic drugs, antimuscarinic drugs, muscarinic blockers, and anticholinergic drugs
  • Anticholinergic drugs: produce selective blockade of muscarinic receptors—not all cholinergic receptors
muscarinic antagonists anticholinergic drugs1
Muscarinic Antagonists(Anticholinergic Drugs)
  • Certain drugs (antihistamines, tricyclic antidepressants, phenothiazine antipsychotics) have prominent antimuscarinic actions.
  • Use with caution—or not at all—with patients receiving other muscarinic antagonists.
muscarinic antagonists anticholinergic drugs2
Muscarinic Antagonists(Anticholinergic Drugs)
  • Atropine
    • Best known muscarinic antagonist
    • Found in nature
    • Mechanism of action
      • No direct effect of its own
      • Muscarinic receptor blockade
muscarinic antagonists anticholinergic drugs3
Muscarinic Antagonists(Anticholinergic Drugs)
  • Atropine
    • Pharmacologic effects (receptor blockade)
      • Heart
      • Exocrine glands
      • Smooth muscle
      • Eye
      • CNS
      • Dose dependency of muscarinic blockade
      • Pharmacokinetics
muscarinic antagonists anticholinergic drugs4
Muscarinic Antagonists(Anticholinergic Drugs)
  • Atropine (cont’d)
    • Therapeutic uses
      • Preanesthetic medication
      • Disorders of the eye
      • Bradycardia
      • Intestinal hypertonicity and hypermotility
      • Muscarinic agonist poisoning
      • Peptic ulcer disease
      • Asthma
      • Biliary colic
muscarinic antagonists anticholinergic drugs5
Muscarinic Antagonists(Anticholinergic Drugs)
  • Atropine (cont’d)
    • Adverse effects
      • Xerostomia (dry mouth)
      • Blurred vision and photophobia
      • Elevation of intraocular pressure
      • Urinary retention
      • Constipation
      • Anhidrosis
      • Tachycardia
      • Asthma
muscarinic antagonists anticholinergic drugs6
Muscarinic Antagonists(Anticholinergic Drugs)
  • Atropine (cont’d)
    • Drug interactions
      • Avoid combining atropine with other drugs capable of causing muscarinic blockade
    • Preparations, dosage, and administration
      • General systemic therapy
      • AtroPen for cholinesterase inhibitor poisoning
      • Ophthalmology
anticholinergic drugs for overactive bladder
Anticholinergic Drugs for Overactive Bladder
  • Overactive bladder (OAB): characteristics and overview of treatment
  • Introduction to anticholinergic therapy of OAB
  • Specific anticholinergic drugs for OAB
    • Oxybutynin (Ditropan, Oxytrol, Gelnique)
      • Syrup
      • Extended-release tablets
      • Transdermal patch and gel
anticholinergic drugs for overactive bladder1
Anticholinergic Drugs for Overactive Bladder
  • Specific anticholinergic drugs for OAB (cont’d)
    • Darifenacin
    • Solifenacin
    • Tolterodine
      • Immediate-release tablets
      • Extended-release capsules
    • Trospium
    • Fesoterodine
other muscarinic antagonists
Other Muscarinic Antagonists
  • Scopolamine
  • Ipratropium bromide
  • Antisecretory anticholinergics
  • Dicyclomine
  • Pirenzepine and telenzepine
  • Mydriatic-cycloplegics
  • Centrally acting anticholinergics
toxicology of muscarinic agonists
Toxicology of Muscarinic Agonists
  • Source of muscarinic poisoning
    • Direct-acting muscarinic agonists
    • Cholinesterase inhibitors
  • Symptoms
    • Result from excessive activation of muscarinic receptors
  • Treatment
    • Muscarinic blocking agent, such as atropine
toxicology of muscarinic antagonists
Toxicology of Muscarinic Antagonists
  • Sources of antimuscarinic poisoning
    • Natural products
    • Selective antimuscarinic drugs
    • Drugs with pronounced antimuscarinic properties
toxicology of muscarinic antagonists1
Toxicology of Muscarinic Antagonists
  • Symptoms
    • Dry mouth
    • Blurred vision
    • Photophobia
    • Hyperthermia
    • CNS effects
    • Hot, dry, and flushed skin
toxicology of muscarinic antagonists2
Toxicology of Muscarinic Antagonists
  • Treatment
    • Physostigmine
    • Inhibitor of acetylcholinesterase
  • Warning
    • Differentiate between poisoning and an actual psychotic episode!