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ANS and drugs
ANS drugs incl. glaucoma
QUESTION | ANSWER |
---|---|
Activation of what receptors causes an increased HR and increased myocardial contractility? | Beta 1 |
Use of what type of drug will cause bronchodilation? Name one? | Beta 2 agonist like albuterol |
What type of drug will cause decreased HR and name one? | Beta 1 antagonist like labetatol |
What is Albuterol? | Beta 2 agonist |
What is Metoprolol? | Beta 1 selective antagonist |
What is Propranolol? | Nonselective Beta antagonist |
What is Atropine? | Muscarinic antagonist |
What is pilocarpine? | Muscarinic agonist |
Chronic exposure to antagonist causes... | up regulation of receptors remember: "anti-up" |
Chronic exposure to agonist causes... | down regulation of receptors |
Adrenal Medulla releases... | epi & norepi |
How would a MAO Inhibitor and ingesting aged cheese effect the body? | Aged or fermented cheese contains tyrosine which is converted to tyramine in the body. MAOIs prevent metabolism of tyramine --> which stims norepi --> HTN crisis! |
Activation of these receptors causes increased HR at SA node, increased impulse velocity at AV node, increased atrial and ventricular contraction & renin release | Beta 1 receptors |
Activation fo these receptors causes Ca influx and smooth muscle contraction | Alpha 1 receptors |
These receptors are mostly presynaptic and inhibits adenylyl cyclase which causes decreased NT release | Alpha 2 receptors |
activation causes smooth muscle relaxation | Beta 2 receptors |
Activation causes lypolysis | Beta 3 receptors |
activations causes smooth muscle contraction and glandular secretion | muscarinic M3 receptors |
Difference between alpha and muscarinic receptors? | they're located in different areas of the body |
activation causes decrease SA node activity, decrease force of atrial contraction & decreased velocity at AV node with decrease rate | Muscarinic M2 receptor |
Sympathetic inervation of eye | iris sphincter muscle contraction --> pupillary dilation & cilliary muscle relaxed --> far vision improved |
drugs that dilates pupil WITHOUT causing cycloplegia | Alpha 1 agonists. ophthalmic phenylephrine, mitodrine, tolterodine |
dilates pupils and also causes cycloplegia | atropine or tropicamide |
Activation of muscarinic M3 receptors | bronchoconstriction, increased secretions |
an M3 antagonist used for COPD? | ipratroprium & tiotropium |
Why is ipratroprium not useful in asthma? | Asthma is not cholinergic related disease as is COPD |
What are the effects of Alpha 2 receptor activation on the gut? | relaxed & decreased digestion |
What are the effects of Muscarinic receptor parasympathetic activation on the gut? | increased gastric secretions, relaxed sphincters with increased motility & increased motility d/t increased smooth muscle tone |
What would be of use with ulcer with too much acid secretion? | muscarinic antagonist |
Effects of activation of muscarinic receptors on bladder | detrusor contraction & trigone relaxation --> micturation |
What do you give someone with an overactive bladder? | muscarinic blocker |
Which is better for pupillary dilation & why? Muscarinic antagonist or alpha 1 agonist | Alpha 1 agonist does not cause cycloplegia |
What is mechanism by which pulse rate, B/P and PVR change with an infusion of norepinephrine? | Norepinephrine stimulates A1 = vasoconstriction and increased PVR therefore increased B/P; baroreceptors will then cause decreased HR. |
What is mechanism by which pulse rate, B/P and PVR change with an infusion of isoproteronol? | isoproteronol is a nonselective Beta agonist therefore increased HR, so decreased B/P & no vasoconstriction so no change in PVR. |
Muscarine | M3 agonist in poisonous mushrooms |
Symptoms of eating poisonous mushrooms that contain muscarine | excess salivation, bronchoconstriction,increased sweating, diarrhea, increased urinary urge, increased lacrimation, constricted pupils with blurry vision,N&V,hypotension with resultant reflex tachycardia |
Alpha & Beta receptors are found in which part of ANS? | sympathetic. so stimulatation is for "fight or flight" |
Muscarinic receptors found in which part of ANS? | parasympathetic. so stimulation is for "rest & digest" |
Activation of Alpha receptors | vasoconstriction, pupillary dilation, |
In anaphylaxsis--why give epi and not norepi | Norepi has a low affinity for B2 receptors and does not relieve bronchoconstriction |
What class of drugs will cause hypotension with subsequent reflex tachycardia? | Alpha 1 blockers |
Drug of choice for a patient with HTN and BPH? | selective Alpha 1 blocker: tamsulosin or alfuzosin |
catacholamine-secreting tumor of the adrenal medulla | pheochromocytoma |
Would use use an alpha or beta blocker on a patient with pheochromocytoma? | Alpha - specifically an nonselective reversible alpha blocker such as phentolamine or nonselective irreversible alpha blocker phenoxybenzomine. Giving a beta blocker without an A1 blocker would cause unopposed vasoconstriction and a HTN crisis |
What is the advantage of using albuterol over epinephrine or isoproteronol | Albuterol is selective for Beta 2 agonist only. Epi hits all receptors and Isoproteronol is not selective so way too many side effects. |
What is Terbutaline and whats it used for? | Beta 2 agonist. Useful for smooth muscle relaxtion in bronchioles as well as uterus. |
What would you do for a patient whose IV infusion of Neosynephrine had extravasated? | Alpha 1 vasoconstricts --> administer SQ an Alpha blocker like phentolamine |
Side effect of B1 agonist administration | skeletal muscle tremors |
A1 selective antagonists for HTN | Prazosin Terazosin Doxazosin |
Treatment for nasal congestion? | Alpha 1 agonist |
Danger of prolonged topical phenylephrine use for nasal congestion? | down regulation of alpha receptors with resultant rebound congestion |
Non-selective Beta antagonist drug names? | Propranolol, Nadolol, Pindolol |
Selective Beta 1 Agonists drug names? | metoprolol, atenolol, bisoprolol |
How can you tell generic selective beta blockerss from non-selective beta blockers? | Selective beta generics all start with a B-E-A-M. |
Beta blocker used for migraine prophylaxsis | propranolol --> reduces frequency, duration and intensity by preventing vasoconstriction. Also blocks prostaglandin production. |
Would use you use a selective or nonselective beta blocker in a COPD patient? | Selective. non-selective beta blockers may percipitate bronchospasm |
CNS side effects of beta blockers? | depression, fatigue, nightmares, insomnia |
What is the precaution for DM patients taking beta blockers | Beta blockers block epi & norepi --> loss of response to hypoglycemia & no glyconeogenesis, so no increase in BS. |
Danger of abruptly discontinuing a beta blocker? | rebound HTN, tachycardias d/t up regulation of beta receptors |
Ophthalmic beta blocker activity in glaucoma? | decreased aqueous humor production |
Alpha 2 agonist use in glaucoma? | decrease aqueous humor production & increase outflow |
clonidine | centrally acting alpha agonist used for HTN |
Yohimbe | alpha 2 antagonist - promotes penile erection |
Why can't you use acetylcholine as a drug? | very non-specific, will act on nicotinic receptors as well as muscarinic--> too many adverse side effects AND its half life is only seconds. |
Drug of choice to help diagnose why a mysthenia gravis patient is experiencing increased muscle weakness? | Endoproprium |
A MG patient, who has been well controlled on medications, presents with complaint of increased weakness. The patient gets weaker after edrophonium administration, why? | Medication for MG is too high. If there is already too much endogenous acetylcholine from overmedication, edrophonium will make it even worse by increasing Ach-->over stim of N receptors-->receptors can't repolarize--> increased weakness |
Acetylcholinesterase inhibitor | physostigmine, neostigmine, pyridostigmine, edrophonium |
MOA of acetylcholinesterase inhibitor? | binds to acetylecholineesterase which rapidly hydrolyzes acetylcholine into acetate and choline |
Which has a longer half-life pyrostigmine or neostigmine? | Neostigmine is an NH4 quartanary ammonium (highly charged, polar) so it is NOT lipid soluable and doesn't last long in the body whereas pyrostigmine is (non-charged,non-polar)with a longer duration. |
What would you administer to a person who had ingested poisonous mushrooms containing muscarine? | Muscarine is a muscarinic agonist so you would administer a muscarinic antagonist like atropine. |
What is Sarin? | a nerve gas that is an irreversible acetylcholinesterase inhibitor used by terrorist groups to kill people (i.e., subway in Japan incident) |
What is the difference between reversible and irreversible acetylcholinesterase inhibitors? | Irreversible inhibitors have a phosphate-oxygen bond that is not easily broken whereas the reversible inhibitors have carbon-oxygen bond that is easily broken. |
What are Organophasphates? | Irreversible acetylcholine inhibitors |
Malathion and Parathion | organophosphate insecticides |
What antidote is given for exposure to irreversible AcHe inhibitors | cholinesterase reactivator -->2-PAM / pralidoxime and a muscarinic blocker -->atropine in multiple doses |
Topical parathion medication? | Ovide for head lice |
What's the difference between neostigmine, physostigmine and organophosphates? | physostigmine is reversible and crosses the BBB. neostigmine is reversible but does not cross BBB. organophosphates are irreversible and cross the BBB. |
Stimulation of cholinergic receptors in the CNS cause what types of symptoms? | confusion, ataxia, slurred speech, loss of reflexes, convulsions, coma, central respiratory paralysis |
How does 2-PAM treat Sarin exposure? | breaks the phosphate-oxygen bond |
Do you have a period of time before you must administer 2-PAM to someone with a Sarin exposure? | NO. Must be given quickly because aging of the phosphorylated enzyme complex make the phosphate-oxygen bond stonger/more stable and IT CAN'T BE BROKEN. |
Can you use 2-PAM for neostigmine OD? | No. neostigmine has a carbon-oxygen bond not a phosphate-oxygen bond. |
Muscarinic anatgonist for overactive bladder? | oxybutinin, tolterodine, darifenacin, solifenacin |
Muscarinic antagonist for IBS? | dicyclomine, hyoscymine |
Belladonna alkaloids with muscarinic antagonist activity | jimsonweed, deadly nightshade, black henbane, scopolomine |
Side effects of muscarinic blockers? | dry mouth, blurry vision |
Jimsonweed ingestion can cause what type of symptoms? | similar to atropine overdose: hallucinations, delirium, confusion, pupillary dilation with blurry vision, dry mouth, no tears or sweat, vasodilation of cutaneous blood vessels. |
Topical opthalmic medications that will dilate pupils? Which is preferable? | Muscarinic blocker like atropine and Alpha 1 agonist like phenylephrine. Alpha 1 is preferable because it does not blur the vision like the muscarinic blocker will. |
Muscarinic antagonist used preoperatively for its sedative and amnesic effects? | scopolamine |
Muscarinic receptors in heart are located primarily where? | Atria, very few in ventricles |
Does atropine work in parathion poisoning? | No. won't block by itself need to add 2-PAM |
Clogged trebecular meshwork which blocks aqueous humor flow with resultant increase in intraocular pressure and eventual blindness if left untreated. | Open angle glaucoma |
Drugs of choice to treat open angle glaucoma | beta blocker and alpha 2 agonist |
Topical non-selective beta blocker glaucoma drugs? | timolol, carteolol, levobunolol |
Topical selective B1 blocker glaucoma drugs? | betaxolol, levobetaxolol |
Topical Alpha 2 blocker glaucoma drugs? | brimonidine and apraclonidine |
A & B activator glaucoma drugs? | epinephrine and dipivefrin |
What is the MOA of ophthalmic epi? | binds to beta 2 receptor cells of trabecullar meshwork and makes"less clogged" up so increases outflow of aqueous humor. Also decreases AH production |
What is ophthalmic Alpha 2 agonist activity? | decreased AH production |
What is ophthalmic muscarinic antagonist activity? | relaxes ciliary muscle; dilates pupil |
Ophthalmic muscarinic agonist gluacoma drugs? | pilocarpine and carbochol |
Ophthalmic muscarinic agonist activity? | contracts ciliary muscle; constricts pupil |
Effect of ophthalmic muscarinic agonist on open angle glaucoma? | binds muscarinic receptor-->ciliary muscle contracts which is connected to trabecullar meshwork-->pulls on meshwork-->opens up the clog and pumps out AH into Schlem's canal |
Structural defect in the eye that causes a narrow angle between the iris and cornea which obstructs the trabecullar meshwork causing a rpid rise in intraocular pressure | Narrow or Closed angle glaucoma |
Drugs of choice to treat narrow angle glaucoma? | cholinomimetics - contracts iris sphincter muscle which pulls iris away from trabecullar meshwork increasing outflow of AH |
What precipitates an acute episode of narrow angle glaucoma? | dilation of pupils from ophthalmic drops |
Muscarinic agonist that helps with dry mouth caused by Sjorgens syndrome? | civimeline |
Drugs of choice for treatment of Narrow Angle glaucoma? | M agonists - pilocarpine and carbochol and alpha 2 agonists |
Is esmolol a good po drug ? | No. very short half life selective B1, available in IV only |
What is a drug of choice to counteract the bradycardia caused by administration of AcHe Inhibitor like neostigmine? Beta 1 agonist or muscarinic blocker? | Muscarinic blocker. Beta 1 agonist will also cause increased B/P, M blocker won't. Besides neostig is a M agonist, M antagnoist is best. |
Is Alpha 1 blocker good for glaucoma? | No. Would constrict pupil BUT does nothing to decrease AH production or increase its outflow. |
You've given your BPH patient tamulosin but now he's having problems with incontinence. What is a good choice of medications to help him? | muscarinic blocker. No M receptors on the prostate so won't hurt. |
Why administer epi with a local anesthetic before injecting into a hip for pain relief? | decrease bleeding d/t vasoconstriction and prolong action of anesthetic. |
Where do you NOT want to use epi with a local anesthetic? | ears, digits, nose, toes, penis. |
For an overdose of atropine, would you administer physostigmine or pyridostigmine? | physostigmine. Because it crosses the BBB (atropine causes hallucinations & delerium), pyridostigmine doesn't cross the BBB |
You have a patient who suffers from syncope when he stands up secondary to orthostatic hypotension which is not drug induced. What would be a good choice of medications for him? | Alpha 1 agonist for its vasoconstrictive properties |
Name 3 competitive cholinesterase inhibitors that act on the CNS and are used in Alzheimer's Disease? How to they work? | donezepil – Aricept, tacrine - Cognex, rivastigmine - Exelon, galantimine - Reminyl They work to increase acetylcholine in the brain by blocking its destruction by acetylcholinesterase. |
Raynaud's phenomena causes vasoconstriction of the digits, what would be a good drug of choice for this patient? | Alpha 1 antagonist - to block vasoconstriction |
Your HTN patient has begun an exercise program but complains of fatigue during exercise? What type of B/P med could cause this? | Beta blocker. HR won't go up so CO won't increase to meet the increased oxygen demands of the body during exercise. |
You HTN patient who you just placed on meds, complains that every time she stands up she passes out. What type of med could cause this and what do you do? | Alpha 1 blocker can cause profound othostatic hypotension especially in initial doses of the med. Should tell the patient to take before bedtime so these effect will occur during sleep cycle and be gone when she wakes in the morning. |
A young child presents after eating what appears to be jimsonweed. What would you administer to reverse? | AcHe inhibitor, physostigmine because the active substance in jimsonweed is a muscarinic antagonist similar to atropine. |