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Chapter 20: Cholinergic drugs

Terms in this set (39)

Cholinergic drugs
drugs that stimulate the PSNS; also known as cholinergic agonists or parasympathomimetics
What is the purpose of cholinergic drugs?
to mimic the efffects of the PSNS neurotransmitter acetylcholine
Nicotinic receptors
located in the ganglia of PSNS and SNS; can be stimulated by nicotine
Muscarinic receptors
located postsynaptically in the effector organs of PSNS; can be stimulated by muscarine
Direct-acting cholinergic agonists
bind to cholinergic receptors and activate them
Indirect acting cholinergic agonists
inhibit cholinesterase so there can be more ACh available
What are the types of indirect acting cholinergic receptors?
reversible and irreversible
Reversible
bind to cholinesterase for a period of minutes to hours
Irreversible
bind to cholinesterase and form a permanent covalent bond; the body must make new cholinesterase to break these bonds
Drugs effects of cholinergic drugs on intestine and bladder
increased GI secretions, increased GI motility, and increased urinary frequency
Drugs effects of cholinergic drugs on pupils
constriction and reduced intraocular pressure
Drug effects of cholinergic drugs on salivation and sweating
increased salivation and sweating
Drug effects of cholinergic drugs on cardiovascular system?
decreased heart rate and vasodilation
Drug effects of cholinergic drugs on respiratory system?
bronchial constriction and narrowed airways
What occurs at recommended doses of cholinergic drugs?
Affects primarily muscarinic receptors
What occurs at high doses of cholinergic drugs?
nicotinic receptors are stimulated
What usually causes desirable effects?
muscarinic receptor stimulation
What usually causes undesirable effects?
stimulation of nicotinic receptors
Indications for direct acting drugs?
reduce intraocular pressure and glaucoma and intraocular surgery
Bethanechol
-increases GI and bladder tone and motility
-relaxes sphincters in GI and bladder
-postsurgical atony
-oral dose or SQ injection
What are the effects of indirect-acting drugs?
-skeletal muscle contractions, diagnosis and treatment of myasthenia gravis, used to reverse neuromuscular blocking drugs, used to reverse anticholinergic poisoning
Indirect-acting anticholinesterase drugs
used to mild to moderate Alzheimer's disease
What drugs are used to treat Alzheimer's?
donepezil (Aricept), galantamine (Razadyne), and rivastigmine (Exelon)
Adverse effects of cholinergic drugs on cardiovascular system?
bradycardia, hypotension, syncope, conduction abnormalities
What are the advserse effects of cholinergic drugs on CNS?
headache, dizziness, convulsions, ataxia
What are the adverse effects of cholinergic drugs on GI?
abnormal cramps, increased secretions, nausea, and vomiting
What are the effects of cholinergic drugs on repiratory system?
increased bronchial secretions and bronchospasms
What are other effects of cholinergic drugs?
lacrimation, sweating, salivation, miosis
Cholinergic crisis
Severe muscle weakness and respiratory paralysis due to excessive acetylcholine; often seen in patients with myasthenia gravis as an adverse effect of drugs used to treat the disorder
What are the early signs of a cholinergic crisis?
cramps, flushing of the skin, vomiting, and orthostatic hypotension
What occurs when cholinergic drugs interact with anticholinergics, antihistamines or sympathomimetics?
Cholinergic drugs are antagonized, resulting in decreased responses
What is gingko commonly used for?
to prevent memory loss, vertigo, and tinnitus
What are possible adverse effects of gingko?
GI upset, headache, bleeding, and allergic skin reaction
Why does gingko cause bleeding?
because of nsaid interaction
What should patients be assessed for?
GI/GU obstructions, asthma, PUD, CAD
What are the s+s of a patient who was given cholinergic drugs despite an obstruction?
abdominal distension, hypoactive bowel sounds, difficulty passing flatus, nausea, vomiting, and pain
What is the antidote for cholinergics?
Atropine and it should be available in the patient's room for immediate use if needed
What therapeutic effects should a postoperative patient be monitored for?
increased bowel sounds, passage of flatus, occurrence of bowel movements
What should be monitored in patients with Alzheimer's?
improvement in symptoms and improvement in mood and decrease in confusion
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