Cholinergics / Anticholinergics Flashcards
(46 cards)
Name 4 Muscarinic agonists
1) Acetylcholine (Miochol-E)
2) Bethanechol
3) Pilocarpine
- Systemic: Salagen
- Opthalmic: Isopto Carpine
4) Cevemiline
Name 4 reversible Cholinesterase inhibitors
1) Physostigmine
2) Neostigmine (Bloxiverz)
3) Pyridostigmine (Mestinon, Regonol)
4) Donepezil (Aricept)
Name 3 kinds of Irreversible Cholinesterase Inhibitors
Name two compounds in two of these categories
1) Echothiophate ( Phospholine Iodide)
2) Organophosphate insecticides
- Malathion
- Parathion
3) Nerve Agents
- Sarin
- VX
Name a cholinesterase reactivator
Pralidoxime ( Protopam Chloride)
Name a drug that blocks acetylcholine release
**Botulinum toxin ** (BOTOX)
Name 6 Muscarinic Antagonists
1) Atropine
- systemic: AtroPen
- opthalamic: IsoptoAtropine)
2) Scopolamine
3) Dicyclomine
4) Ipratropium
5) Tolterodine
6 ) Tropicamide
Name 4 Direct Acting Muscarinic Agonists
1) Acetylcholine
2) Bethanechol**
3) Pilocarpine** (systemic: Salagen , Opthalmic: IsoptoCarpine)
4) Cevimeline ** (Evoxac)
Name some physiological effects of direct acting muscarinic agonists
GI, Heart Rate, Blood Pressure, bladder, ocular, secretions
- Increased GI motility
- Decreased HR
- Decreased Blood Pressure
- decreased cardiac output
- direct vasodilation
- Contraction of bladder and relaxation of urinary sphincters
- Miosis and decreased intraocular pressure
- Stimulation of secretions
- salivation, lacrimation, GI secretions, sweating, etc.
Therapeutic uses of direct acting muscarinic agonists on Urinary and GI systems and some example medications
GI and Urinary applications (bethanechol)
- Stimulation of peristalsis and increased GI motility
- Formerly used to treat postoperative abdominal distention, gastric atony, adynamic ileus and GERD
- More efficacious therapies are now available
Treatment of urinary retention and inadequate emptying of the bladder
* Postoperative urinary retention
* Diabetic autonomic retinopathy
* Chronic hypotonic, myogenic or neurogenic bladder
Name some ocular therapeutic applications of direct acting Muscarinic Agonists
- Treatment of Glaucoma (carbachol and pilocarpine)
- Opthalmic surgery (induction of miosis)(acetylcholine, carbachol, pilocarpine)
Name some therapeutic uses of direct acting muscarinic agonists for salivary gland dysfunctions and some example medications
Pilocarpine and cevimeline
Xerostomia (dry mouth) due to:
- Head and neck radiation
- Sjorgen syndrome (autoimmune disorder where salivary and lacrimal secretions are compromised)
- They enhance salivary secretion and ease of swallowing
Name 8 adverse effects of direct acting Muscarinic Agonists
BP / HR / Lungs / GI / Urinary / Glandular / Salivary
Mainly the result of unwanted or excessive muscarinic stimulation
- Hypotension
- Bradycardia
- Bronchoconstriction
- Diarrhea
- Cramping
- Urinary incontinence
- Excessive sweating
- Salivation
Name contraindications of direct acting muscarinic agonists
Breathing / Cardiovascular / Stomach / bladder
- Asthma
- Cardiovascular
* Bradycardia
* Hypotension
* Vasomotor instability
* Coronary artery disease - Peptic ulcer disease
- Weakened smooth muscle of the bladder or GI tract (such as after bladder surgery or intestinal anastomosis)
- Urinary or intestinal obstruction
Acetylcholine: What is it used for, rate of metabolism?
Muscarinic Agonist
* Limited use to ophthalmic surgery where rapid miosis is necessary
* When it is administered systemically, it is very rapidly hydrolyzed by “pseudocholinesterase” in the plasma
Bethanechol: Structure, effect on nicotinic receptors and use?
Muscarinic Agonist
* Analog of acetylcholine that is resistant to rapid hydrolysis
* Direct muscarinic agonist with little effect at nicotinic receptors
* Used to stimulate GI motility and treat urinary retention
Pilocarpine: Uses
Muscarinic Agonist
* Used in the treatment of glaucoma and xerostomia due to poor salivary
secretion
Cevimeline: Therapeutic Uses
Muscarinic Agonist
* Used in the treatment of xerostomia due to poor salivary secretion
How do cholinesterase inhibitors work, and name 7 physiological effects
GI / Bladder / HR / BP / Secretions / Eye / Skeletal Muscle / Bronchial
The cholinesterase inhibitors act by preventing the breakdown
of acetylcholine in the synapse
Increased GI motility and secretion
Contraction of bladder and relaxation of sphincters
Bradycardia and hypotension
Increased secretions (salivation, lacrimation, sweating, etc…)
Decreased intraocular pressure
Stimulation of skeletal muscle (therapeutic doses) / paralysis of
skeletal muscle (toxic doses)
Bronchoconstriction
Cholinesterase Inhibitors: Therapeutic uses
Bladder / Neurodegenerative diseases
Treatment of paralytic ileus and atony of the bladder (neostigmine)
- Abdominal distention and acute colonic pseudo-obstruction from a
variety of medical and surgical causes
- Atony (lack of physiological tone) of the bladder detrusor muscle of the urinary bladder
Treatment of Alzheimer disease (donepezil)
- AD patients have reduced cerebral content of choline acetyltransferase (leads to decrease in acetylcholine synthesis and impaired cortical cholinergic function)
- Cholinesterase inhibitors increase cholinergic transmission by
inhibiting cholinesterase at the synaptic cleft and provide modest
symptomatic benefit in patients with AD
Cholinesterase Inhibitors Therapeutic Uses
neuromuscular
Treatment of myasthenia gravis (pyridostigmine) (neostigmine is
less commonly used)
Myasthenia gravis is an autoimmune neuromuscular disorder characterized by fluctuating motor weakness involving ocular, bulbar, limb, and/or respiratory muscles
What causes muscle weakness in Myasthenia gravis, and how do cholinesterase inhibitors help?
The weakness is due to an antibody-mediated, immunologic attack
directed at proteins in the postsynaptic membrane of the
neuromuscular junction (acetylcholine receptors or receptor-associated proteins)
Acetylcholinesterase inhibitors retard the degradation of ACh that
occurs by enzymatic hydrolysis in the neuromuscular junction, resulting in a prolonged effect of ACh
- Variable improvement in strength in patients with MG
- Pyridostigmine provides marke improvement in some patients and little or none in others
Name 2 drugs that can help treat glaucoma, and how they help. Why are they rarely used today?
1 Cholinergic agonist and 1 Cholinesterase Inhibitor
Pilocarpine: Cholinergic agonist
Echothiophate: Cholinesterase inhibitor
Work by contracting the ciliary muscle, these drugs put tension on the trabecular meshwork and increase the outflow of aqueous
humor through the canal of Schlemm
Rarely used today because:
- Ocular side effects such as fixed, small pupils, myopia, and increased subjective visual disturbance related to coexistent cataract
What are some drugs that can protect against poisoning?
Treatment of poisoning with atropine or other antimuscarinic
drugs (physostigmine)
Pyridostigmine is used by the military to protect personnel
against nerve agents used in chemical warfare
What are some adverse effects of Cholinesterase inhibitors
Toxic effects may be severe (cholinergic crisis) especially in
overdose situations (organophosphate insecticide poisoning or
nerve-gas poisoning)
SLUDGE (salivation, lacrimation, urination, defecation, GI
distress, emesis)
Skeletal muscle fasciculation followed by paralysis
Bradycardia, hypotension, shock
Severe miosis
CNS stimulation and seizures followed by coma