Ch. 20: Cholinergic drugs Flashcards
What are the 2 types of cholinergic receptors? Explain the difference between the 2.
Nicotinic - on preganglionic fibers of ANS (both SNS and PSNS)
Muscarinic - on postsynaptic neuron on cardiac muscle, smooth muscles, and glands
What are the 2 abnormalities that characterize Alzheimer’s disease (AD)?
amyloid plaques that form between neurons
neurofibrillary tangles found in neurons
Which brain biochemical is reduced in the hippocampus and cerebral cortex of AD patients? What is its function?
choline actyltransferase - is the catalyst for ACh, which stimulates higher brain functions of learning and memory
What are the classes of cholinergic drugs?
direct-acting and indirect-acting cholinergic agonists
What are the primary uses of cholinergic drugs?
reduce intraocular pressure (IOP) in patients with glaucoma or undergoing ocular sugery
Myasthenia gravis
Alzheimer’s disease
excessive dry mouth (xerostomia) resulting from Sjogren’s syndrome
What are the drug effects of cholinergics?
stimulate the GI and GU tracts --> increased gastric secretions, increased GI motility, increased urinary frequency pupil constriction (miosis) increased salivation sweating decreased HR vasodilation bronchoconstriction
Which direct-acting cholinergic drug can be administered orally? What is its effect?
bethanechol chloride - causes increased bladder and GIT tone and motility, which increases movement of contents
causes relaxation of GI and GU sphincters –> emptying
How do indirect acting cholinergic drugs work?
increase ACh concentration at receptor sites by inhibiting cholinesterase (decreases breakdown of ACh at synaptic cleft):
skeletal muscle contraction –> treat Myasthenia gravis
increased brain function –> treat Alzheimers
What are symptoms of cholinergic crisis/overdose?
Early: "SLUDGE" salivation lacrimation urinary incontinence diarrhea GI cramps emesis
Severe: circulatory collapse hypotension bloody diarrhea shock cardiac arrest
What is the antidote for cholinergic overdose?
atropine - for early signs of cholinergic toxicity
epinephrine - for severe cardiovascular reactions or bronchoconstriction
What should the nurse remember when administering anticholinergics to treat myasthenia gravis?
PO meds should be given 30 minutes before meals to allow onset and therapeutic effects to decrease dysphagia
What are the 2 common side effects of cholinergic drugs that should be monitored by the nurse?
dizziness due to hypotention
ataxia/gait imbalance
–> both cause risk for falls
T/F: PO Cholinergics can be given without regard to meals
False: they should be given with meals to reduce GI upset
A patient is taking bethanechol chloride before meals (an anticholinergic). After 3 days, he calls his health care provider’s office and complains of nausea and vomiting. Which of the following instructions is appropriate?
a. if these symptoms continue, take the doses in the evening
b. if this continues, you can skip a dose and try it again tomorrow
c. take this medication with meals to reduce GI upset
d. continue to take on an empty stomach to reduce GI upset
C
When giving IV cholinergic drugs, the nurse must watch for symptoms of a cholinergic crisis. Which of the following is a symptom of this reaction?
a. tinnitus
b. hypotension
c. hypertension
d. peripheral tingling
B
