Cholinergic drugs promote the action of which neurotransmitter
Acetylcholine ACH
Cholinergic drugs promote the action of which ANS
parasympathetic
Name the two classes of cholinergic drugs
1) cholinergic agonist
2) anticholinesterase drugs
What is the effect of cholinergic agonists?
mimic the action of ACH
Are cholinergic agonists administered IV or IM?
no - broken down immediately and/or cause cholinergic crisis
What effect do cholinergic drugs have on the following target organs
- salivary glands
- heart rate
- blood vessel tone
- bronchioles
- GI tract activity
- bladder
- pupils
- increase salivation
- decrease HR
- vasodilation
- bronchiole constriction
- increase GI activity
- increase bladder tone and contraction
- constrict pupils
Anticholinesterase drugs work how?
block the enzyme acetylcholinesterase, preventing the breakdown of ACH, thus stimulating the parasympathetic system.
Can anticholinesterase drugs be given IM or IV?
yes
Anticholinesterase drugs are used in anesthesia for what reason?
To reverse the effects of anticholinergics
Name some anticholinesterase drugs commonly used in anesthesia/parr?
- edrophonium
- neostigmine
- physostigmine
- pyridostigmine
How do anticholinergic drugs work?
block ACH from stimulating cholinergic receptors.
- interrupt PNS impulses
Do anticholinergics work on muscarinic or nicotinic sites or both?
muscarinic
What anticholinergics are commonly used in anesthesia/parr?
atropine
scopolamine
glycopyrollate
dicyclomine
Why are anticholinergics are commonly used in anesthesia/parr?
- treat bradycardia or arrhythmias
- decrease secretions
- block vagal reflexes such as decreased HR
- relax bowels
- bladder spasms
- biliary colic
- counteract neuromuscular blocking drugs
Adrenergic drugs affect which ANS?
sypathomimetic
What are the two groups of adrenergic drugs?
- catecholamines
- noncatecholamines
How to catecholamines act?
stimulate the SNS
- vasoconstriction
- increase HR
- bronchodilation
What are some commonly used catecholamines?
- dobutamine
- dopamine
- epinephrine
- norepinephrine (levarteronol)
- isoproterenol
What effect do catecholamines have on
a) alpha receptors
b) beta receptors
c) dopamine receptors
a) alpha - activate or excite
b) beta - block or inhibit (except in the heart)
c) increase dopamine activity
What effect do catecholamines have on the heart?
- inotropes - increase the force of heart contraction (increase o2 consumption)
- chronotropes - increase heart rate
What is a potential devastating side effect?
PVC's - ventricular irritibility
Which adrenergics act mostly on the beta receptors?
dobutamine and isopropteronol
Epinephrine acts on which receptors?
a) alpha
b) beta
c) dopamine
a & b
Norepinephrine acts on which receptors?
a) alpha
b) beta
c) dopamine
a - alpha
Dobutamine and isopropterenol acts on which receptors?
a) alpha
b) beta
c) dopamine
beta
Dopamine acts on which receptors?
B) dopamine
Alpha stimulating catecholamines are used to treat what?
hypotension. Especially caused by
a) vasodilation
b) blood loss
Beta stimulating catecholamines are used to treat what?
- bradycardia
- heart block
- low Cardiac output
- make heart more responsive to defibrillation
therefore used for v fib; asystole; cardiac arrest
- allergic reactions
- bronchospasms
Non-catecholamine adrenergics have what effects?
Stimulate the SNS
- vasoconstriction
- bronchodilation
- decongestion
- smooth muscle relaxation
Some examples of non-catecholamine adrenergics:
- albuterol (beta)
phenylephrine (alpha)
metaproterenol (beta)
terbutaline (beta)
ephedrine (beta)
isoproterenol
terbutaline (smooth muscle relax)
Alpha Adrenergic blockers (sympatholytic) work how?
interrupt the actions of the catecholamines epinephrine and norepinephrine at alpha receptors
What effects do alpha sympatholytics have?
- smooth muscle relaxation
- vasodilation
- decrease BP
When are alpha sympatholytics used
- hypertension
- peripheral vascular disease
- pheochormocytoma
- vascular headaches
How do beta-blockers work?
prevent stimulation of SNS by inhibiting catecholamine action