1. Drugs Affecting the
Parasympathetic
Nervous System
Nelia B. Perez RN, MSN

2. 1. It is the main
neurotransmitter in the
PNS.
a. MAO
b. Ach
c. ACTH
d. ADH

3. 2. This is the alkaloid
substance found in
tobacco.
a. Caffeine
b. Sugar
c. Tar
d. Nicotine

4. 3. Found at the
parasympathetic
postganglionic nerve
endings and acts like Ach.
a. Nicotinic Receptors
b. Ganglionic receptors
c. Muscarinic receptors
d. Sympathetic receptors

5. 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
•.

6. 5. It blocks cholinergic and
nicotinic receptors.
a.Reversible Inhibitors
b.Irreversible inhibitors
c.Cholinesterase
d.anticholinesterase

7. 6. These are derivatives of
organophosphate compounds
which is widely used as
insecticides, pesticides and
chemical warfare agents.
a. Cholinesterase
b. Reversible Inhibitors
c. Irreversible Inhibitors
d. None of these

8. 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 Crisis
b. hypertensive crisis
c. Stroke
d. None of these

9. 8. It binds to muscarinic
receptors and act by
competitive antagonism
of ACH.
a. Cholinergic drugs
b. Cholinesterase
c. anticholinesterase
d. Anticholinergic Drugs

10. 9. It is the opposing system
of the SNS
a. ANS
b. PNS
c. CNS
d. CVS

11. 10.Major effects of the
Cholinergic drugs.
a. STONES
b. DUALS
c. SLUDGE
d. SMUDGE

12. 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.

13. Drugs Affecting the Parasympathetic
Nervous System
ACH ACH ACH
ACH ACH
ACH ACH ACH
ACH
ACH
ACH
ACH ACH ACH
Acetylcholinesterase

14. Drugs Affecting the Parasympathetic
Nervous System
Receptors
Muscarinic Receptors Nicotinic Receptors
N-1 N-2

15. Drugs Affecting the Parasympathetic
Nervous System
Nicotinic Receptors
Nicotinic-I Receptors Nicotinic-II Receptors
Found at ganglions of
Found at Neuromuscular junction of
Sympathetic and Parasympathetic
Skeletal muscles.
Post- ganglionic fibers

16. Drugs Affecting the Parasympathetic
Nervous System
Ganglion, Nicotinic I receptor
Sympathetic Fibers
Pre-ganglionic Post-ganglionic Fiber
Fiber
Adrenergic Receptor
Ganglion, Nicotinic I receptor
Parasympathetic Fibers
Pre-ganglionic Fiber Post-ganglionic Fiber
Muscarinic Receptors
Somatic Fibers
Nicotinic II Receptors

17. 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.

18. Drugs Affecting the Parasympathetic
Nervous System
Nicotinic I
Drugs
Ganglionic Ganglionic
Stimulants Blockers

19. 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.

20. Drugs Affecting the Parasympathetic
Nervous System
Parasympathetic
Drugs
Cholinergic Anti-cholinergic
Drugs Drugs

21. Drugs Affecting the Parasympathetic
Nervous System
Cholinergic
Drugs
Direct Acting Indirect Acting
Cholinergic Drugs Cholinergic Drugs

22. Drugs Affecting the Parasympathetic
Nervous System
Direct Acting Cholinergic Drugs
• Bind to muscarinic receptors.
• Produces ACH like effect.
• Slowly inactivated by
acetylcholinesterase.

23. 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)

24. Cholinergic Drugs
“rest and digest” system
“SLUDGE”
 Salivation
 Lacrimation
 Urinary incontinence
 Diarrhea
 Gastrointestinal cramps
 Emesis

25. Cholinergic Drugs
Drug 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

26. Drugs Affecting the Parasympathetic
Nervous System
Pharmocological Effects
• Increase GI secretion and
motility
• Increase in genitourinary
activity.
• Bronchoconstriction

27. Drugs Affecting the Parasympathetic
Nervous System
Pharmocological Effects
• Miosis
• Vasodilatation (lower BP)
• Decrease heart rate.

28. Drugs Affecting the Parasympathetic
Nervous System
Direct Acting Main Use
Acetylcholine Miotic
Bethanecol Nonobstructive urinary
retention
Carbachol Treatment of glaucoma
Methacholine Miotic
Pilocarpine Treatment of glaucoma

29. Drugs Affecting the Parasympathetic
Nervous System
Indirect Acting
Cholinergic Drugs
(Anticholinesterases)
Reversible Irreversible
Inhibitors Inhibitors

30. Drugs Affecting the Parasympathetic
Nervous System
ACH ACH
ACH
ACH ACH ACH
ACH ACH
ACH
ACH
ACH
ACH ACH ACH
Acetylcholinesterase
Anticholinesterases

31. Drugs Affecting the Parasympathetic
Nervous System
Reversible Inhibitors
• Blocks cholinergic and nicotinic
receptors.
• Use in the diagnosis and treatment
of myasthenia gravis.

32. 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

33. Drugs Affecting the Parasympathetic
Nervous System
Clinical Use
• Topical use in glaucoma
• Treatment of myasthenia gravis
• Treatment of urinary retention and
intestinal stasis

34. Drugs Affecting the Parasympathetic
Nervous System
Clinical Use
• Treatment of Alzheimer’s disease.
• Antidote to skeletal muscle blockers.
• Antidotes to anticholinergic drug
poisoning.

35. Drugs Affecting the Parasympathetic
Nervous System
Indirect-Acting
Cholinergic Drug
Reversible Irreversible
Ambenonium Isoflurophate
Edrophonium
Neostigmine
Physostigmine
Pyridostigmine

36. Drugs Affecting the Parasympathetic
Nervous System
Adverse and Toxic Effect
• Nausea
• Vomiting
• Diarrhea
• Blurred vision

37. Drugs Affecting the Parasympathetic
Nervous System
Adverse and Toxic Effect
• Excessive sweating
• Muscular tremors
• Bronchoconstriction
• Bradycardia

38. Drugs Affecting the Parasympathetic
Nervous System
Adverse and Toxic Effect
• Hypotension
• Mucular paralysis
• Respiratory arrest

39. 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.

40. Drugs Affecting the Parasympathetic
Nervous System
Treatment
• Stop anticholinesterase drug
administration.
• Give atropine to block the effect of
excess muscarinic stimulation

41. 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.

42. 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

43. 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

44. Drugs Affecting the Parasympathetic
Nervous System
Pharmacological 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.

45. Drugs Affecting the Parasympathetic
Nervous System
Pharmacological 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.

46. Drugs Affecting the Parasympathetic
Nervous System
Ocular Effect
• Mydriasis
• Cycloplegia
• Increases Intraocular
pressure.

47. Drugs Affecting the Parasympathetic
Nervous System
Adverse and Toxic Effect
• Cause by excessive blockage of the
Parasympathetic Nervous System.
• Dry mouth.
• Visual disturbances
• Urinary retention
• Constipation.

48. Drugs Affecting the Parasympathetic
Nervous System
Adverse and Toxic Effect
• Dryness of the skin
• Flushing
• Hyperpyrexia
• CNS stimulation and depression

49. Drugs Affecting the Parasympathetic
Nervous System
Anticholinergic Drugs
Belladonna Alkaloids Synthetic Drugs
Atropine Semisynthetic Drug Diclyclomine
Scopolamine Isopropamide
Hyoscyamine Homatropine Propantheline
Methantheline

50. 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

51. 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

52. 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

53. Thank You
and
See You nexT week!