Upload
nhelia-santos-perez
View
930
Download
1
Tags:
Embed Size (px)
DESCRIPTION
Citation preview
Drugs Affecting the Parasympathetic Nervous System
Nelia B. Perez RN, MSN
1. It is the main neurotransmitter in the PNS.a. MAOb. Achc. ACTHd. ADH
2. This is the alkaloid substance found in tobacco.a. Caffeineb. Sugarc. Tard. Nicotine
3. Found at the parasympathetic postganglionic nerve endings and acts like Ach.a. Nicotinic Receptorsb. Ganglionic receptorsc. Muscarinic receptorsd. Sympathetic receptors
4. They produces ACH like effect and slowly inactivated by acetylcholinesterase.a. Direct Acting Cholinergic Drugs
b. Muscarinic drugs c. Adrenergic drugs d. Indirect acting cholinergic drugs
• .
• .
5. It blocks cholinergic and nicotinic receptors.
a.Reversible Inhibitorsb.Irreversible inhibitorsc.Cholinesterased.anticholinesterase
6. These are derivatives of organophosphate compounds which is widely used as insecticides, pesticides and chemical warfare agents. a. Cholinesteraseb. Reversible Inhibitorsc. Irreversible Inhibitorsd. None of these
7. A situation where there is excessive drug dosage in patients with myasthenia gravis and a high concentration of ACH causes excessive stimulation of the muscarinic receptors.a. Cholinergic Crisisb. hypertensive crisisc. Stroked. None of these
8. It binds to muscarinic receptors and act by competitive antagonism of ACH.a. Cholinergic drugsb. Cholinesterasec. anticholinesterased. Anticholinergic Drugs
9. It is the opposing system of the SNSa. ANSb. PNSc. CNSd. CVS
10.Major effects of the Cholinergic drugs.a. STONESb. DUALSc. SLUDGEd. SMUDGE
Drugs Affecting the Parasympathetic Nervous System
Parasympathetic Nervous System
• Neurotransmitter is ACH
• The receptors are called cholinergic receptors.
• Drugs that bind to cholinergic receptors and produced effects similar to ACH are referred to as cholinergic drugs.
Drugs Affecting the Parasympathetic Nervous System
ACHACH
ACH
ACH
ACH
ACH ACH
ACH
ACH
ACH
ACH
ACH
ACH
ACH
Acetylcholinesterase
Drugs Affecting the Parasympathetic Nervous System
Nicotinic ReceptorsMuscarinic Receptors
Receptors
N-1 N-2
Drugs Affecting the Parasympathetic Nervous System
Nicotinic Receptors
Nicotinic-II Receptors
Found at ganglions of Sympathetic and Parasympathetic Post- ganglionic fibers
Found at Neuromuscular junction ofSkeletal muscles.
Nicotinic-I Receptors
Parasympathetic Fibers
Post-ganglionic Fiber
Sympathetic Fibers
Pre-ganglionic Fiber
Pre-ganglionic Fiber
Post-ganglionic FiberAdrenergic Receptor
Muscarinic Receptors
Drugs Affecting the Parasympathetic Nervous System
Nicotinic II Receptors
Ganglion, Nicotinic I receptor
Ganglion, Nicotinic I receptor
Somatic Fibers
Drugs Affecting the Parasympathetic Nervous System
Nicotine
• Alkaloid obtained from tobacco.
• Stimulate the NI receptors at low doses.
• Block the NII receptors at high doses.
Drugs Affecting the Parasympathetic Nervous System
GanglionicBlockers
GanglionicStimulants
Nicotinic I Drugs
Drugs Affecting the Parasympathetic Nervous System
Muscarinic Receptors
• Found at the parasympathetic postganglionic nerve endings
• Drugs that act like ACH at these receptors are referred to as cholinergic or muscarinic drugs.
• Drugs that block ACH at the muscarinic receptors are referred to as anticholinergic or antimuscarinic drugs.
Drugs Affecting the Parasympathetic Nervous System
Anti-cholinergicDrugs
CholinergicDrugs
ParasympatheticDrugs
Drugs Affecting the Parasympathetic Nervous System
Direct ActingCholinergic Drugs
CholinergicDrugs
Indirect ActingCholinergic Drugs
Drugs Affecting the Parasympathetic Nervous System
Direct Acting Cholinergic Drugs
• Bind to muscarinic receptors.
• Produces ACH like effect.
• Slowly inactivated by acetylcholinesterase.
Cholinergic Drugs Drugs that stimulate the
parasympathetic nervous system (PSNS) opposing system to the SNS Known as: cholinergic agonists or
parasympathomimetics Mimic the effects of the PSNS neurotransmitter:
acetylcholine (Ach)
Cholinergic Drugs“rest and digest” system
“SLUDGE”
Salivation Lacrimation Urinary incontinence Diarrhea Gastrointestinal cramps Emesis
Cholinergic DrugsDrug Effects
Stimulate intestine and bladder Increased gastric secretions Increased gastrointestinal motility Increased urinary frequency
Stimulate pupils Constriction (miosis) Reduced intraocular pressure
Increased salivation and sweating Cardiovascular effects
Decreased heart rate Vasodilation
Respiratory effects Bronchial constriction, narrowed airways
Drugs Affecting the Parasympathetic Nervous System
Pharmocological Effects
• Increase GI secretion and motility
• Increase in genitourinary activity.
• Bronchoconstriction
Drugs Affecting the Parasympathetic Nervous System
Pharmocological Effects
• Miosis
• Vasodilatation (lower BP)
• Decrease heart rate.
Direct Acting Main Use
Acetylcholine Miotic
Bethanecol Nonobstructive urinary retention
Carbachol Treatment of glaucoma
Methacholine Miotic
Pilocarpine Treatment of glaucoma
Drugs Affecting the Parasympathetic Nervous System
Drugs Affecting the Parasympathetic Nervous System
IrreversibleInhibitors
ReversibleInhibitors
Indirect ActingCholinergic Drugs
(Anticholinesterases)
Drugs Affecting the Parasympathetic Nervous System
ACHACH
ACH
ACH
ACH
ACHACH
ACH
ACH
ACH
ACH
ACH
ACH
ACH
Acetylcholinesterase
Anticholinesterases
Drugs Affecting the Parasympathetic Nervous System
Reversible Inhibitors
• Blocks cholinergic and nicotinic receptors.
• Use in the diagnosis and treatment of myasthenia gravis.
Drugs Affecting the Parasympathetic Nervous System
Irreversible Inhibitors
• Derivatives of organophosphate compounds.
• Widely used as insecticides, pesticides and chemical warfare agents.
• Long duration of action
Drugs Affecting the Parasympathetic Nervous System
Clinical Use
• Topical use in glaucoma
• Treatment of myasthenia gravis
• Treatment of urinary retention and intestinal stasis
Drugs Affecting the Parasympathetic Nervous System
Clinical Use
• Treatment of Alzheimer’s disease.
• Antidote to skeletal muscle blockers.
• Antidotes to anticholinergic drug poisoning.
Drugs Affecting the Parasympathetic Nervous System
Indirect-ActingCholinergic Drug
Reversible
AmbenoniumEdrophoniumNeostigmine
PhysostigminePyridostigmine
Irreversible
Isoflurophate
Drugs Affecting the Parasympathetic Nervous System
Adverse and Toxic Effect
• Nausea
• Vomiting
• Diarrhea
• Blurred vision
Drugs Affecting the Parasympathetic Nervous System
Adverse and Toxic Effect
• Excessive sweating
• Muscular tremors
• Bronchoconstriction
• Bradycardia
Drugs Affecting the Parasympathetic Nervous System
Adverse and Toxic Effect
• Hypotension
• Mucular paralysis
• Respiratory arrest
Drugs Affecting the Parasympathetic Nervous System
Cholinergic Crisis
• Excessive drug dosage in patients with myasthenia gravis.
• High concentration of ACH causes excessive stimulation of the muscarinic receptors.
• High concentration of ACH causes blockade of nicotinic receptor.
Drugs Affecting the Parasympathetic Nervous System
Treatment
• Stop anticholinesterase drug administration.
• Give atropine to block the effect of excess muscarinic stimulation
Drugs Affecting the Parasympathetic Nervous System
Cholinergic Crisis
• Excessive exposure to sprays containing derivatives of irreversible anticholinesterase.
• High concentration of ACH causes excessive stimulation of the muscarinic receptors.
• High concentration of ACH causes blockade of nicotinic receptor.
Drugs Affecting the Parasympathetic Nervous System
Treatment
• Remove person from the exposure.
• Give Pralidoxime to reactivate the anticholinesterase enzyme.
• Give atropine to block the effect of excess muscarinic stimulation
Drugs Affecting the Parasympathetic Nervous System
Anticholinergic Drugs
• Binds to muscarinic receptors.
• Act by competitive antagonism of ACH.
• Prototype drugs: Belladonna alkaloids, atropine and scopolamine
Drugs Affecting the Parasympathetic Nervous SystemPharmacological Action
• Increase heart rate.
• Increase the secretions of the respiratory tract and may cause bronchoconstriction.
• Reduce salivary and GI tract.
• Inhibit urinary peristalsis and voiding of urine.
Drugs Affecting the Parasympathetic Nervous SystemPharmacological Action
• Depressant effects on the CNS causing drowsiness and sedation.
• At high doses cause both stimulation and depression of the CNS
• At toxic doses excitation, delirium, hallucination and profound CNS depression leading to respiratory arrest and death.
Drugs Affecting the Parasympathetic Nervous System
Ocular Effect
• Mydriasis
• Cycloplegia
• Increases Intraocular pressure.
Drugs Affecting the Parasympathetic Nervous SystemAdverse and Toxic Effect
• Cause by excessive blockage of the Parasympathetic Nervous System.
• Dry mouth.
• Visual disturbances
• Urinary retention
• Constipation.
Drugs Affecting the Parasympathetic Nervous System
Adverse and Toxic Effect
• Dryness of the skin
• Flushing
• Hyperpyrexia
• CNS stimulation and depression
Drugs Affecting the Parasympathetic Nervous System
Anticholinergic Drugs
Belladonna Alkaloids
AtropineScopolamineHyoscyamine
Semisynthetic Drug
Homatropine
Synthetic Drugs
DiclyclomineIsopropamidePropanthelineMethantheline
Nursing Implications Assess for allergies, presence of GI or GU obstructions,
asthma, peptic ulcer disease, or coronary artery disease
Perform baseline assessment of vital signs and systems overview
Medications should be taken as ordered and not abruptly stopped
The doses should be spread evenly apart to optimize the effects of the medication
Overdosing can cause life-threatening problems. Only physicians should adjust the dosages
Nursing Implications
• Encourage patients with myasthenia gravis to take medication 30 minutes before eating to help improve chewing and swallowing
• When cholinergic drugs are prescribed for Alzheimer’s disease, be honest with caregivers and patients that the drugs are for management of symptoms, not a cure
• Therapeutic effects of anti-Alzheimer’s drugs may not occur for up to 6 weeks
Nursing Implications
Monitor for therapeutic effects Alleviated signs and symptoms of myasthenia gravis In postoperative patients with decreased GI peristalsis,
look for:
Increased bowel sounds Passage of flatus Occurrence of bowel movements
In patients with urinary retention/hypotonic bladder, urination should occur within 60 minutes of bethanechol administration
• ALSO monitor for adverse effects
Thank You
and
See you next week!