What is the MOA of muscarinic agonist?

binds to muscarinic receptors to cause activation.

What are the effects of muscarinic activation?

1. bradycardia,

2. increased secretion from sweat, salivary, bronchial, and gastric glands; contraction

3.  contraction of intenstinal and bronchial smooth muscle

4.  contraction of the bladder

5.  mitosis and accomodation for near vision

What is bethanechol - the prototype of muscarinic agonists -primarily used for?

urinary retention

given po only

non-selective

What are the S&S's of muscarinic agonist poisoning?

How do you treat it?

profuse  salivation, tearing, visual disturbances, bronchospasm, diarrhea, bradycaria, and hypotension

Tx:  Atropine (muscarinic blocking agent) and provide supportive therapy.

How do muscarinic antagonists work?

blocks AcH at muscarinic receptors and thereby,

1.  Increases HR

2.  reduces secretion of salivary, sweat, gastric, bronchial glands

3. relaxes intestinal and bronchial smooth muscle

4.  causses urinary retention

5.  acts in CNS to produce excitation (low doses) and delerium & hallucinations (high doses)

What do you use muscarinic antagonists (anti-cholinergics) for?

1.  preanesthesia

2.  opthalmic exams

3.  reversal of bradycardia

4.  tx of OAB

5.  manage muscarinic agonist poisoning

What are the classic SE's of anticholinergic drugs?

1. dry mouth

2. blurred vision

3.  photophobia

4.  tacycardia

5. urinary retention

6. constipation

7. suppression of sweating

What other drugs have antimuscarinic actions?

1. antihistamines

2.  TCA

3. phenothizine antipsychotics

Should be used cautiously, especially in those receiving atropine or other muscarinic antagonists.

What are the symptoms of muscarinic antagonists poisoning?

1.  blurred vision

2.  photophobia

3. hyperthermia

4. hallucinations and delerium

5.  hot, dry, flushed skin

What is the antidote for muscarinic antagonist poisoning?

physostigmine, a cholinesterase inhibitor

What is the prototype for muscarinic antagonists?

What is it's effect?

Atropine which blocks AcH at muscarinic receptors

Think boy and bear!

1.  Increased HR

2. Dried secretions

3. decreased GUT motility

4. Pupillary dlation

5.  Decreases urge to void

What are the adverse effects of muscarinic agonists?

Think "pig"

Excessive cholingergic

hypotension, bradycardia, dysrhthmias, gi distress, salivation, asthma exacerbation, urgency, CNS, toxicity if given IM or IV

Memory Tip:  DUMBBELSS = diarrhea & dec bp, urination, miosis, bronchoconstriction, bradycardia, excitability, lacrimation, sweating, salivation.