Cholinergic agonists andCholinergic antagonists Flashcards
Chapter 32-33
What do cholinergic agonists do?
-Act on same site as the neurotranmitter of acetylcholine (ach) and increase the activity of the ACh receptor sites throughout the body
What is cholinergic agnoist also known as?
Parasympathomimetics
because their actions mimics the action of the parasympathetic nervous system
What do cholinergic agonist mimic?
Mimic action of the PSNS
-Contracting smooth muscles
-Increasing secretions
-Dilate blood vessels
-Decrease Heart rate
-Constrict pupils
What is the difference between direct vs indirect Cholinergic agonist?
-Indirect Cholinergic agonist inhibit the enzyme acetylcholinesterase, and this enzyme breaks down ACh
This causes ACh to stay in the synapse, More ACh is available at the receptors, causing the effects to last longer
-Direct-acting cholinergic agonists bind to cholinergic receptors causing a increase in stimulation
What are cholinergic effects?
Sludge
-Salivation
-Lacrimation
-Urinary incontinence
-Diarrhea
-Gastrointestinal cramps
-Emesis
Dumbbells
-Diarrhea
-Urination
-Miosis
-Bronchoconstriction
-Bradycardia
-Emesis -Lacrimation
-Lethargy
-Salivation/sweating
What is Bethanechol ( Urecholine)?
Direct acting cholinergic agonist
-Can be used for post op, post partum urinary retention
-Atony of bladder( Detrusor muscle loses ability to contract making it harder to empty bladder)
What is the therapeutic action of Bethanechol
Direct acting cholinergic agonist
-Mimic ACh simulation
Which includes:
-Slowed heart rate
-Decreased myocardial contractility
-Vasodilation
-Bronchoconstriction
-Increased bronchial mucus secretions
-Increased Gi activity and secretions
-Increased bladder tone , relaxation of GI and bladder sphincters
-Pupil constriction
-Increases detrusor muscle,relaxing sphincter to improve bladder emptying
What are indications of Bethanechol (Urecholine)?
Direct acting cholinergic agonist
-Increase bladder tone
-Increase Gi secretions
-Increase urinary excretion
-Opthalmic-induce miosis to relieve Introculor pressure
Help treat non obstructive postoperative and postpartum urinary retention and to treat neurogenic bladder atony
-Drug is not destroyed by acetylcholinesterase, the effects are longer lasting than with stimulation
-Mostly for POST Op surgery or POST OP giving birth
What are contras against Bethanechol (Urecholine)?
Direct acting cholinergic agonist
-Bradycardia
-Hypotension
-Vasomotor instability( like hot flashes and sweating problems)
-Coronary artery disease.
(These could be made worse with the cardiac,cardiovascular suppressing effects
-Parkison disease
-peptic ulcers, intestinal obstruction
-recent Gi surgery,
-Asthma could be exacerbated by increased ps effect
-Epilepsy and parkinsons disease could be affected by stimulation of ACh receptors in brain
What cautions should there be while taking bethanechol (Urecholine)?
Direct acting cholinergic agonist
Pregnancy and lactation because it is unknown if there are adverse effects on the fetus or neonate
What are adverse effects of bethanechol (Urecholine)?
Direct acting cholinergic agonist
-Bradycardia, heartblock, hypotension, cardiac arrest related to cardiac- suppression
GI: Nausea, vomiting, cramps, diarrhea increased salivations, increased involuntary defection
Dehydration due to increased GI motility and resultant diarrhea
-Urgency to use bathroom due to relaxed sphincter muscles and stimulation of bladder muscles
What are drug to drug interactions with bethanechol (Urecholine)?
Direct Acting Cholinergic Agonists
-risk of cholergic affects if given w acetylcholinesterase inhibitors like neostigmine
Describe indirect Acting Cholinergic agonists?
-Prevents breakdown of ACh, allowinf more stimulation of receptors. Reacts chemically with the acetylcholinsterase to prevent it from breaking down (ACH)
-Used for myasthenia Gravis
-Used for Alzheimer disease
What is Myasthenia Gravis?
-Autoimmune disease, chronic disorder of the neuromuscular junction
-Patients body makes antibodies that destricts the Ach receptors
-ACh is a nuerotransmiterr used at nerve for muscle synaps, so it is needed for muscle movement strength
-If ACh receptors are blocked and can not be stimulated, muscle activity is decreased
What is used for Myasthenia Gravis?
Indirect Acting Cholinergic Agonists
pyridostigmine (Mestinon)
What is pyridostigmine (Mestinon)?
Indirect Acting cholinergic Agonists
What does pyridostigmine (Mestinon) do?
Indirect Acting cholinergic Agonists
-Improves muscle strength by allowing ACH accumulation
-Antidote to neuromuscular junction blockers/irreversible acetylcholinesterase inhibiting drugs:Increases survival after exposure to nerve gas
-Reversible cholinesterase inhibitor that increases levels of ACh, facilitating transmissions at the neuromuscular junction
What are contras to pyridostigmine (Mestinon)?
Indirect Acting Cholinergic Agonists
-Bradycardia
-Obstructions (Do not give with urinary retention because it can make stimulation worse)
-pregnancy(Stimulate uterus and induce labor)
What are cautions to pyridostigmine (Mestinon)?
Any clinical picture that could be worsened by PSNS stimulation
What are drug to drug interactions with pyridostigmine (Mestinon)?
anti-cholinergic, aminoglycosides, steroids
What is a donepezil (Aricept)
Indirect Acting cholernigic agonist for alzheimer disease
What does donepezil (Aricept) do?
Works centrally in brain to increase ACh and slows neuronal degradation
Does not prevent dz
What are contras of donepezil (Aricept?
Indirect Acting Cholinergic Agonists
-Bradycardia
-Obstructions (Do not give with urinary retention because it can make stimulation worse)
-pregnancy(Stimulate uterus and induce labor)
What are cautions to have with donepezil (Aricept)?
Any clinical picture that could be worsened by PSNS stimulation
-Renal and liver dz
