Drugs in Ophthalmology

Question 1

Symp and parasymp innervation of the iris causes what, resp? This innervation to the ciliary body controls modification of the production of what and the thickness of what?

Answer 1

Pupillary dilation and constriction. Aqueous production and lens thickness.

Question 2

Accomodation involves what 3 actions?

Answer 2

Thickening of the lens, convergence of the eyes, and pupillary constriction.

Question 3

Absent light reflex (no pup const), but pupillary constriction when focusing on a near object is intact is called?

Answer 3

Light-near dissociation

Question 4

Light-near dissociation is seen in what 3 clinical syndromes?

Answer 4

Parinaud’s syndrome (in pineal tumors), Argyll Robertson syndrome (syphilis), and Adie syndrome (a benign parasymp deficit).

Question 5

In the eye, nicotinic receptors are found in what muscles and muscarinic receptors are found in what structures?

Answer 5

Eom’s, ciliary body (circular fibers constrict pupil and longitudinal fibers place tension on trabec meshwork) and iris sphincter (constrict pupil).

Question 6

Direct parasympathetic muscarinic agonists in the eye include what?

Answer 6

ACh (Miochol), Carbachol, methacholine, pilocarpine

Question 7

Direct parasympathetic muscarinic agonists in the eye have what effect?

Answer 7

Pupillary constriction, increased aq outflow

Question 8

Direct parasympathetic muscarinic agonists in the eye are used for what?

Answer 8

In cataract surgery and tx of glaucoma

Question 9

Parasympathetic muscarinic antagonists in the eye have what effect? What structure do they ‘paralyze’?

Answer 9

Pupillary dilatation, paralysis of ciliary body

Question 10

Parasympathetic muscarinic antagonists in the eye have what use?

Answer 10

Cycloplegia for eye exams and to improve comfort during eye inflammation (uveitis).

Question 11

Parasympathetic muscarinic antagonists in the eye include what drugs?

Answer 11

Atropine, scopolamine, homatropine, cyclopentolate, tropicamide.

Question 12

The only application in ophtho for a parasympathetic nicotinic receptor manipulation is in diagnosing MG. This indirect agonist is named what and has what action?

Answer 12

Edrophonium (Tensilon) destroys acetylcholinesterase.

Question 13

In the sympathetic system of the eye, NE is released which acts on what structures? Indicate the actions carried out in parantheses.

Answer 13

Iris dilator muscle (dilates pupil)
Superior palpebral muscle of Muller (lifts eyelid)
Ciliary epithelium (facilitates aq production)
Smooth muscle of ocular bv’s (dilates bv’s)
Trabecular meshwork (increases outflow of aq)

Question 14

Direct sympathetic agonist phenylephrine action

Answer 14

Mimic NE a1 - dilation of pupil

Question 15

Direct sympathetic agonist L-epinephrine action

Answer 15

alpha and beta

Question 16

Direct sympathetic agonist dipivalyl epinephrine (propine) action

Answer 16

prodrug of epi; alpha and beta

Question 17

Direct sympathetic agonist bromondine tartrate (Alphagan) action

Answer 17

selective a2 agonist which suppresses aq humor production

Question 18

Direct sympathetic agonist apraclonidine action

Answer 18

alpha agonist, no crossing of BBB and has minimal effect on systemic bp

Question 19

Direct sympathetic agonist clonidine action

Answer 19

lowers introcular pressure thru CNS effects

Question 20

Indirect sympathetic agonist cocaine action

Answer 20

prevents reuptake of NE

Question 21

Indirect sympathetic agonist hydroxyamphetamine (paradrine) action

Answer 21

Releases NE

Question 22

Sympathetic antagonist dapiprazole action

Answer 22

Reverses action of tropicamide and phenylephrine. Blockage of alpha-adrenergic receptors in smooth dilator muscle of iris.

Question 23

Sympathetic antagonist timolol action

Answer 23

Non-specific b1&2

Question 24

Sympathetic antagonist betaxolol action

Answer 24

b1 blocker

Question 25

Sympathetic antagonist carteolol action

Answer 25

non-specific b1&2 blocker

Question 26

Sympathetic antagonist levobunolol action

Answer 26

b2 blocker

Question 27

Sympathetic antagonist metipranolol action

Answer 27

non-selective b1 and b2 blocker without significant intrinsic sympathomimetic activity, only a weak membrane stabilizing activity and weak myocardial depressant

Question 28

Epinephrine cpds are thought to increase aqueous outflow by doing what? Tx's what?

Answer 28

Dilating the episcleral vessels. Glaucoma

Question 29

Beta-blockers such as timolol, betaxolol, and levobunolo reduce intraocular pressure by what? Tx's what?

Answer 29

Reducing aq prod at the ciliary process. Glaucoma.

Question 30

Parasympathomimetics lower intraocular pressure to tx glaucoma through what action?

Answer 30

Spreading the trabecular meshwork thru contraction of the ciliary muscles

Question 31

Acetazolamide, ehtoxzolamide, and methazolamide (orals) and dorzolamide HCl and brinzolamide (topicals) are what type of drugs that treat glaucoma by what mechanism of action?

Answer 31

Carbonic anhydrase inhibitors interfere with the active transport of Na through Na-K-ATPase pump, acting at the ciliary body to reduce the production of aqueous.

Question 32

What class of drugs are now the main therapy used to tx glaucoma? How do they work (hint: it's unique)? What's the most effective one in reducing intraocular pressure?

Answer 32

Prostaglandin analogs inc uveoscleral outflow without any effect on aqueous flow or trabecular outflow facility. Latanaprost (Xalatan).

Question 33

All prostaglandins are contra'd in what conditions and have what adverse effects?

Answer 33

Cystoid macular degeneration, herpes, can cause growth of lid lashes, change in iris color.

Question 34

Timolol (a first line med) contraindications

Answer 34

CHF, asthma, bradycardia, overtime may cause tachyphyaxis

Question 35

Brimodine (a first line med) contraindications

Answer 35

With MAOI can cause fatigue/drowsiness, follicular conjunctivitis

Question 36

Dorzolamide HCl (first line) contraindication

Answer 36

Allergies to sulfonamides

Question 37

3 syndromes assoc'd with pupillary dilatation which are important to recognize

Answer 37

Intracranial aneurysms (trauma to CNIII which parasymp's travel w/), Adie's syndrome (viral infection or trauma to ciliary ganglion), and pharmacologic blockade

Question 38

Confirm Horner's with what? Use what drug to distinguish pregang (serious) or postgang (benign)? In each of the cases, describe what occurs in comparison to a normal pupil which dilates.

Answer 38

Cocaine 10%. Paredrine 1%. Fails to dilate with cocaine. Dilates with paredrine if primary or second order lesion, fails to if third order.

Question 39

Denervation hypersensitivity occurs in Adie's but not from an acutely traumatized nerve from an aneurysm. What do you use to distinguish these?

Answer 39

Pilocarpine 1/8% or methacholine 2.5% cause constriction at these very low doses of cholinergic drugs.

Question 40

If you rule out Adie's and want to be certain the dilatation is not due to an aneurysm, giving pilocarpine 1% should constrict the pupil for anyone. What's it called when this pupillary response is still blocked?

Answer 40

Pharmacologic blockade produced by a cycloplegic (muscarinic antagonists)

Question 41

PLEASE STUDY THE AEs LISTED IN TABLE-4 ON PG 17 OF THE HANDOUT

Answer 41

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