Autonomic Eye Drugs - Trachte Flashcards
How do parasymathetics affect the pupil?
Constrict it!
ACh on the postganglionic recptor
How do symathetics affect the pupil?
Dilate it
Noreprinephrine on postgnaglionic recptor
What drugs can you use to promote mydriasis?
through autonomic nervous system
Sympathomimetics (stimulate sympathetics)
Inhibitors of parasympathetic nervous system (atropine)
How does cocaine and amphetamine affect the pupils?
cocaine blocks the reuptake of NE into the neuron
This allows NE to continue to affect the alpha-1 receptor and keep the pupil dilated
Amphetamine reverses the pump of NE to affect the alpha1 recptor and dialte the eyes
What receptor does phenylephrine affect?
It is an aplha1 adrenergic stimulant
it is used in eye drops to dilate pupils
If pupils are unequal diameter in a patient, then you want to test function of parasympathetics.
No good drugs to test this though….
What should you do instead?
test if eye can respond to a muscarinic agonist
If eye responds to pilocarpine with miosis, then problem has to be with the nerve (third nerve palsy)
If eye does not respond to pilocarpine, then problem has to be with the eye itself (Atropinic mydriasis)
Which of the following is most likely to cause mydriasis: Acetazolamide Acetylcholine Pilocarpine Phenylephrine Timolol
Phenyephrine!
Alpha-1 agonist y’all
Which of the following is most likely to produce miosis: Acetazolamide Amphetamine Pilocarpine Phenylephrine Timolol
Pilocarpine
Drugs producing miosis?
Nicotine activates parasympathetic nerves
Muscarinic agonists such as Pilocarpine (Pilocar), acetylcholine (Miochol)
Agents preventing acetylcholine degradation
Physostigmine (Isopto eserine), Ecothiophate (phospholine iodide), demecarium (Humorsol), isofluorophate (floropryl)
a1 receptor antagonists
TERAZOSIN-not used to treat eye disease but can have ocular side effects
Norepinephrine depleting agents- Reserpine (Serpasil)- have the potential of causing ocular side effects (miosis; ptosis)
If a patient exhibits miosis and you wish to treat pharmacologically, which of the following is best?
Atropine Pilocarpine Phenylephrine Reserpine Terazosin
Atropine
Why because you want to take your foot off the gas rather than put your foot on the brake with gas still on
(it’s an antagonist, rather than an agonist in the opposite direction)
What drugs treat glaucoma?
Treatments for Glaucoma:
Agents enhancing aqueous humor outflow
- Muscarinic agonists (pilocarpine)
- Prostaglandins (Latanaprost)
- Epinephrine
Agents suppressing aqueous humor production
- ß adrenergic antagonists (Timolol)
- Alpha2 adrenergic agonists (Aproclonidine)
- Carbonic anhydrase inhibitors (Acetazolamide)
This is annoying but I think important to know:
What are the receptors for these sympathetic responses:
Mydriasis- contract pupillary dilator =
Superior tarsal muscle to hold eyelid open =
Relax ciliary muscle for distant vision =
Enhance aqueous humor formation =
Inhibit aqueous humor formation =
Mydriasis- contract pupillary dilator = Alpha1
Superior tarsal muscle holds eyelid open = Alpha1
Relax ciliary muscle for distant vision = Beta2
Enhance aqueous humor formation = Beta
Inhibit aqueous humor formation = Alpha2
What receptors are all parasympathetic eye system actions mediated by?
Muscarinic receptors
How do parasympathetics affect miosis and near vision?
focus eye for near vision THROUGH ciliary muscle contraction
constrict pupil (miosis) THROUGH pupillary sphincter contraction
Mydriatic agents can have what bad complication?
Precipitate closed-angle glaucoma!
