Nervous System Flashcards
muscarinic antagonists
atropine
muscarinic agonists (parasympathomimetic)
bethanechol
ganglionic-stimulating agents
nicotine
cholinesterase inhibitors (ChE)
physostigmine, neostigmine
neuromuscular-blocking agents
tubocurarine
adrenergic agonists (sympathomimetic)
epinephrine (adrenaline)
adrenergic antagonists (block alpha and beta receptors)
prazosin (alpha adrenergic antagonist), propanolol (beta adrenergic antagonist)
nicotine receptors
release of epinephrine from adrenal medulla; located at neuromuscular junction of skeletal muscle; causes skeletal muscle contraction
muscarinic receptors
decreased secretions from lungs, stomach, intestines, sweat glands; decrease in HR; smooth muscle contraction in bronchi and GI tract; miosis (sphincter contraction) and accommodation (ciliary contraction); voiding due to contraction of detrusor muscle and relaxation of trigone and sphincter muscles
alpha 1 receptors
mydriasis d/t radial muscle contraction; veins and arterioles are activated to constrict; decreased peripheral resistance and increased blood pressure; male sex organs are activated to promote ejaculation; contraction of prostatic capsule, trigone, and sphincter muscles
dopamine receptors
dilates blood vessels in the kidneys
beta 1 receptors
predominant receptor found on the heart; decreased HR, increased contraction force, and increased conduction through AV node; increased lipolysis; release of renin by the kidneys
beta 2 receptors
dilates bronchi; relaxes uterine smooth muscle; vasodilation of arterioles in heart, lungs, and skeletal muscle; slightly decreased peripheral resistance; increased glycogenolysis in the liver and muscles; skeletal muscle contraction
medications affecting the nervous system: general points
adaptive changes within brain with prolonged exposure; increased therapeutic effect; decreased side effects; tolerance and physical dependence; do not stop abruptly
Parkinson’s disease
treatment uses two main classes: medications that activate dopamine receptors (directly or indirectly) and medications that block acetylcholine receptors
seizure disorders
different types of seizures respond to different medications; usually require life-long management; medications must be discontinued slowly over 6 weeks to several months
schizophrenia
clinical course includes semi-remission punctuated by acute exacerbations; positive symptoms (agitation, delusions) medications: conventional antipsychotic [thorazine], atypical antipsychotic [clozapine]; negative symptoms (social withdrawal, poor self-care) medications: atypical antipsychotic [clozapine]; cognitive symptoms (difficulties with memory and learning); initial doses are high and given throughout the day; Maintenon doses given at bedtime
depression
symptom relief can take 1 to 3 weeks and possibly 2 to 3 months; three main groups: tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and monoamine oxidase inhibitors (MAOIs)
bipolar disorder
typically managed with mood stabilisers; antipsychotics and antidepressants may be used during acute episodes of mania or depression; lithium, valproic acid [Depakote], and carbamazepine [Tegretol]
cholinesterase inhibitors: expected action
prevents ACh degradation; increased transmission of nerve impulses by increased ACh
cholinesterase inhibitors: therapeutic uses
increased muscle strength by increasing ACh at neuromuscular junction in myasthenia gravis; reversal of nondepolarising neuromuscular blocking agents (tubocurarine)
cholinesterase inhibitors: adverse effects
excessive muscarinic stimulation; increased GI motility and secretions, bradycardia, and urinary urgency (side effect can be treated with atropine); cholinergic crisis: above plus respiratory depression from neuromuscular blockade
cholinesterase inhibitors: contraindications and precautions
pregnancy C; CI in obstruction of GI and GU systems; caution with seizures, asthma, bradycardia, hypotension, and peptic ulcer disease
cholinesterase inhibitors: interactions
tubocurarine: neostigmine reverse blockade; atropine: counteracts; succinylcholine: increased neuromuscular blockade