Autonomic Drugs Flashcards
Name the direct cholinomimetic agonists
Bethanechol, carbachol, methacholine, pilocarpine
Use of bethanechol
postoperative ileus, neurogenic ileus, urinary retention
Action of bethanechol
Activate bowel and bladder smooth muscle
resistant to AChE
Use of cabachol
constricts pupil and relieves intraocular pressure in glaucoma
Use of methacholine
challenge test for diagnosing asthma
Mech of methacholine
stimulates muscarinic receptors in airway when inhaled –> bronchoconstriction
Use of pilocarpine
potent stimulator of sweat, tears and saliva
open-angle and closed-angle glaucoma
Action of pilocarpine
constricts the ciliary muscle of the eye (good for open-angle glaucoma)
constricts the pupillary sphincter (good for closed-angle glaucoma)
resistant to AChE
Name the indirect cholinergic agonists
donepezil, galantamine, rivastigmine, edrophonium, neostigmine, physostigmine, pyridostigmine
Use of donepezil, galantamine and rivastigmine
alzheimers disease –> increase in ACh
Use of edrophonium
historically to dx myasthenia gravis
now dx MG via anti-AChR antibody test
Use of neostigmine
postoperative and nuerogenic ileus and urinary retention
myasthenia gravis
reversal of neuromuscular junction blockade (postoperative)
DOES NOT CROSS BBB
Use of physostigmine
anticholinergic toxicity
CROSS BBB
Use of pyridostigmine
myastenia gravis (long-acting)
DOES NOT CROSS BBB
Caution with cholinomimetic agents in who?
Asthmatics and pts with COPD to avoid exacerbation of disease
also peptic ulcers
Cholinesterase inhibitor poisoning
often due to organophosphates (irreversibly inhibit AChE)
DUMBBELSS
diarrhea, urination, miosis, bradycardia, bronchoconstriction, excitation of muscle, lacrimation, sweating, salivation
Antidote to organophosphate poisoning
atropine (competitive inhibitor) + pralidoxime (regenerates AChE if given early)
Name the muscarinic antagonists
atropine, homatropine, tropicamide, benztropine, glycopyrrolate, hyoscyamine, dicyclomine, ipratropium, tiotropium, oxybutynin, solifenacin, tolterodine, scopolamine
Organ system affected by atropine, homatropine, and tropicamide
eye
Action of atropine, homatropine, and tropicamide
produce mydriasis and cycloplegia
Organ system action of benztropine
CNS
Action of benztropine
Parkinson disease
Acute dystonia
Organ system action of glycopyrrolate
GI and respiratory
Action of glycopyrrolate
parenteral: preoperative use to reduce airway secretions
oral: drooling, peptic ulcers
Organ system for hyoscyamine, dicyclomine
GI
Action of hyoscyamine, dicyclomine
antispasmodics for irritable bowel syndrome
Organ system for ipratropium and tiotropium
respiratory
Action of ipratropium and tiotropium
inhibit bronchoconstriction so good for asthmatics and pts with COPD
Organ system for oxybutynin, solifenacin, tolterodine
Genitourinary
Action of oxybutynin, solifenacin, tolterodine
use to tx patients with urinary incontinence/overactive bladder
reduce bladder spasms
Organ system for scopolamine
CNS
Action of scopolamine
motion sickness
Multiple effects of atropine
Eye - pupil dilation and cycloplegia Airway - decrease secretions Stomach - decrease acid secretion Gut - decrease motility Bladder - decrease urgency in cystitis
blocks DUMBBeLLS (excitation is nicotinic receptors)
Toxicity of atropine
HOT (due to decreased sweating), DRY (no secretions), RED (flushed), BLIND (cycloplegia), MAD (disoriented)
can cause acute angle-closure glaucoma in elderly due to mydriasis, urinary retention in men with BPH, and hypertermia in infants
Jimson weed (Datura)
causes gardener’s pupil (mydriasis due to plant alkaloids)
Mech of tetrodotoxin
binds fast voltage-gated Na+ channels in cardiac and nerve tissue, preventing depolarization (blocks AP without changing resting potential)
Effects of tetrodotoxin
nausea, diarrhea, paresthesias, weakness, dizziness, loss of reflexes
Tx of tetrodotoxin poisoning
supportive
How acquire tetrodotoxin
eating improperly prepared pufferfish (Japan)
Mech of ciguatoxin
opens Na+ channels causing depolarization (symptoms often confused with colinergic poisoning)
Effects of ciguatoxin
DUMBBELS PLUS
temperature-related dysesthesia (cold feels hot, hot feels cold)
How acquire ciguatoxin
consumption of reef fish (ciguatera fish, barracuda, snapper, moray eel)
Treatment of ciguatoxin
supportive
Effects of scombroid poisoning
acute-onset burning sensation of the mouth, flushing of the face, erythema, urticaria, pruritis, headache
may be anaphylaxis-like presentation (brhoncospasms, angioedema, hypotension)
Mech of scombroid poisoning
bacterial histidine decarboxylase converts histidine –> histamine
histamine not degraded by cooking (misdiagnosed as allergy to fish)
How acquire scombroid poisoning
caused by consumption of dark-meat fish (bonito, mackerel, mahi-mahi, tuna) improperly stored at warm temperature
Treatment of scombroid poisoning
antihistamines
if needed give antianaphylactics (epi)
Albuterol, salmeterol receptors
B2 > B1
Use of albuterol and salmeterol
albuterol for acute asthma; salmeterol for long-term asthma or COPD control
Dobutamine receptors
B1 > B2, alpha
Use of dobutamine
heart failure (HF) (inotropic > chronotropic), cardiac stress testing
Dopamine receptors
D1 = D2 > beta > alpha
Use of dopamine
unstable bradycardia, HF, shock; inotropic and chronotropic alpha effects predominate at high doses
Epinephrine receptors
beta > alpha
Use of epi
anaphylaxis, asthma, open-angle glaucoma
alpha effects predominate at high doses
significantly stronger effects at beta2 receptors than norepinephrine
Isoproterenol receptors
B1 = B2 with NO alpha effects
Use of isoproterenol
electrophysiologic evaluation of tachyarrhythmias
can worsen ischemia
Norepinephrine receptors
alpha 1 > alpha 2 > beta 1
NO beta2 effects
Use of norepinephrine
hypotension (but decreases renal perfusion)
Phenylephrine receptors
alpha 1 > alpha 2
Use of phenylephrine
hypotension (vasoconstrictor), ocular procedures (mydriatic), rhinitis (decongestant)
Effect of amphetamine
indirect general agonist, reuptake inhibitors, also releases stored catecholamines
Use of amphetamine
Narcolepsy, obesity, ADHD
Effect of cocaine
indirect general agonist, reuptake inhibitor (NET)
Use of cocaine
causes vasoconstriction and local anesthesia
never give beta blockers if cocaine intox is suspected because can cause unopposed alpha activation and extreme hypertension
Effect of ephedrine
indirect general agonist, releases stored catecholamines
Use of ephedrine
nasal decongestion, urinary incontinence, hypotension
Clonidine receptor
alpha2- agonist
Use of clonidine
hypertensive urgency
does not decrease renal blood flow
ADHD and Tourette syndrome
Toxicity of clonidine
CNS depression, bradycardia, hypotension, respiratory depression, miosis
alpha-methyldopa receptor
alpha-2 agonist
Use of alpha-methyldopa
used for hypertension in pregnancy
Toxicity of alpha-methyldopa
direct Coombs positive hemolysis
SLE-like syndrome (also seen with procainamide and hydralazine)
Name the non-selective alpha blockers
phenoxybenzamine (irreversible)
phentolamine (reversible)
Toxicity of the non-selective alpha blockers
orthostatic hypotension, reflex tachycardia
Use of phenoxybenzamine
pheochromocytoma (used preoperatively) to prevent catecholamine (hypertensive) crisis
Use of phentolamine
give to patients on MAO-inhibitors who eat tyramine-containing foods (to prevent the vasoconstriction and hypertensive crisis)
Name the alpha1 selective antagonist
(-osin ending)
prazosin, terazosin, doxazosin, tamsulosin
Use of alpha 1 selective antagonist
urinary symptoms of BPH
Prazosin - PTSD
All BUT TAMSULOSIN - hypertension
Toxicity of alpha1 selective antagonist
1st dose orthostatic hypotension, dizziness, headache
Name the alpha2 selective antagonist
mirtazapine
Use of mirtazapine
depression
Toxicity of mirtazapine
sedation, increased serum cholesterol, increased appetite
Name the B1 selective antagonists
acebutolol (partial agonist), atenolol, betaxolol, esmolol, metoprolol
Name the non-selective beta antagonists
nadolol, pindolol (partial agonist), propranolol, timolol
Name the non-selective alpha and beta antagonists
carvedilol and labetalol
What is special about nebivolol?
cardiac selective B1 blockade with stimulation of B3 receptors, which activate NO synthase in the vasculature
Use of beta-blockers in angina pectoris
decrease heart rate and contractility, resulting in decreased O2 consumption
Use of beta-blockers in MI
beta-blockres (metoprolol, carvedilol and bispropolol) decrease mortality
Use in SVT of metoprolol and esmolol
short acting Decrease AV conduction velocity (class II antiarrhythmics)
Use of beta-blockers in hypertension
decrease cardiac output, decrease renin secretion (due to B1-receptor blockade on JGA cells)
Use of beta-blockers in HF
decrease mortality in chronic HF
Use of beta-blockers in glaucoma (timolol)
decrease secretion of aqueous humor)
Toxicity of beta-blockers
impotence, CV adverse effects (bradycardia, AV block, HR), CNS adverse effects (seizures, sedation, sleep alterations), asthma/COPD exacerbations
dyslipidemia specifically in metoprolol use
