Eye pharm (Linger)

Question 1

Primary Applications of Ocular Drugs

Answer 1

Fundoscopic examination

Diagnostic (e.g., anisocoria)

Therapeutic

• Allergic conjunctivitis
• Infections
• Glaucoma
• Strabismus
• Uveitis

Surgical

• Preoperative
• Intraoperative
• Postoperative

Question 2

Acetylcholinesterase inhibitors, muscarinic agonists such as pilocarpine, and β-blockers are among the drugs used to manage patients with glaucoma. They also share properties that are particularly relevant to patients with asthma. Which statement summarizes best what that relevance is?

A. Contraindicated for people with asthma
B. Degranulate mast cells, cause bronchocontriction
C. Raise IOP in patients with glaucoma and asthma
D. Trigger bronchoconstriction by activating H1 receptors
E. Useful for acute asthma, not for ambulatory patients

Answer 2

Contraindicated for people with asthma

Question 3

Systemic Distribution of Ocular Drugs

Answer 3

Tears –> cornea–> aqueous humor–> iris–> systemic circulation

Tears–> conjunctiva–> sclera–> ciliary body–> systemic circulation

also cornea sclera

Question 4

Autonomic Innervation of the Eye

Answer 4

Iris circular (Sphincter)- parasympathetic

Iris radial (dilator)- sympathetic

ciliary circular - parasympathetic

Question 5

Iris circular

Answer 5

(Sphincter)

muscarinic agonist–> contraction; miosis

muscarinic antagonist –> relaxation; mydriasis

Question 6

iris radial

Answer 6

alpha -1 agonist –> contraction; mydriasis

Question 7

ciliary circular muscle

Answer 7

muscarinic agonist–> contraction; accomodation

muscarinic antagonist –> relaxation; cycloplegia

Question 8

Carbachol, pilocarpine

Answer 8

Intraocular use for miosis during surgery, glaucoma

Side effects: Corneal edema, miosis, induced myopia, decreased vision, brow ache, retinal detachment

Question 9

Echothiophate

Answer 9

Use for Glaucoma, accommodative esotropia (strabismus)

side effects: Blurred vision, burning sensation in eye, iritis, night blindness, uveitis

Question 10

Atropine, homatropine, cyclopentolate, tropicamide, etc.

Answer 10

Use for: Cycloplegic retinoscopy, dilated funduscopic exam, cycloplegia

side effects: Photosensitivity, blurred vision, burning sensation in eye, raised IOP

Question 11

pharmacologic eval of anisocoria

Answer 11

pilocarpine- cholinergic agent used for glaucoma/ can be used to test for cholinergic supersensitivity

cocaine - sympathetic agonist at norepinephrine reuptake transporter. Normal eye –> dilation. If smaller pupil does not dilate, then it means there’s not enough norepinaphrine around. Differentiates simple anisocoria from horner’s syndrome.

hydroxyamphetamine - causes release of NE stores. distinguishes preganglionic/ central horner’s (dilation) from postganglionic horner’s (no dilation)

Question 12

horner syndrome

Answer 12

ptosis, miosis, anhydrosis

Question 13

Pharmacologic Evaluation of Anisocoria: Apraclonidine

Answer 13

Alternative with similar efficacy as cocaine test
0.5% solution placed in both eyes
Affected pupil will dilate more than the normal pupil

Question 14

Pharmacologic Evaluation of Anisocoria: Phenylephrine

Answer 14

Alternative with similar efficacy as hydroxyamphetamine test
1% solution placed in both eyes
Normal eye will dilate < 0.5 mm
If postganglionic lesion, affected eye will dilate more than unaffected eye

Question 15

Glaucoma

Answer 15

Among the leading causes of blindness in the US

Increased pressure within the eyeball can result in damage to the optic disk and gradual loss of vision

Risk factors:

• Elevated intraocular pressure (IOP)
• Positive family history
• African-American heritage
• Myopia (nearsightedness)
• Hypertension

Question 16

drugs for glaucoma do one of 2 things

Answer 16

increase drainage

or decrease production of aqueous humor

Question 17

A patient with a history of angle-closure glaucoma experiences a sudden rise of intraocular pressure that is sufficiently severe. In addition to pain there is an imminent risk of permanent vision loss. He requires immediate treatment, one element of which is administration of echothiophate. What enzyme is affected by this drug?

Tyrosine hydroxylase – stimulated
Acetylcholinesterase (AChE) – inhibited
Catechol-O-methyltransferase (COMT) – inhibited
Monoamine oxidase (MAO) – stimulated
DOPA decarboxylase - stimulated

Answer 17

Acetylcholinesterase (AChE) – inhibited

Increasing contraction of the ciliary muscle and the sphincter iris muscle –> constriction of the pupils–> unsmushes the iris, promotes drainage of aqueous humor

Muscarinic agonists like pilocarpine and carbachol can also be used

Question 18

Angle-Closure Glaucoma

Answer 18

AKA closed-angle or narrow-angle
Usually acute
Medical emergency
Surgical iridectomy

Short-term drug therapy with muscarinic agonists; sometimes also AChE inhibitors

Antimuscarinics, some antihistamines (dirty drugs- anti-muscarinic actions), and α1-adrenergic agonists are contraindicated

Question 19

Open-Angle Glaucoma

Answer 19

AKA primary or chronic glaucoma
Most common type
Affects ~3 million Americans
Pharmacotherapy reduces IOP, but may or may not slow progression

Question 20

A variety of ophthalmic drugs, working by several main mechanisms of action, are useful for managing chronic open-angle glaucoma. Which one reduces intraocular pressure by decreasing the formation of aqueous humor, rather than by changing the size of the pupil(s)?

Carbachol
Echothiophate
Pilocarpine
Prazosin
Timolol

Answer 20

Timolol

Question 21

Drugs for Open-Angle Glaucoma: Mechanisms of Action: Decreased Aqueous Secretion

Answer 21

Beta-blockers
Alpha-2-selective agonists
Carbonic Anhydrase Inhibitors (CAIs)

Question 22

Drugs for Open-Angle Glaucoma: Mechanisms of Action: Increased Outflow

Answer 22

Prostaglandin F2α analogs
Alpha-2-selective agonists
Cholinomimetics
- Muscarinic agonists
- Acetylcholinesterase (AChE) inhibitors

Question 23

Prostaglandin F2α Analogs

Answer 23

Prototype: Latanoprost
Other agents: Bimatoprost (Latisse), Travoprost, and Unoprostone
1st line therapy for open-angle glaucoma
Low systemic side effects; ocular side effects include conjunctival hyperemia, irritation, increased number and length of lashes, changes in iris and lash pigmentation
Once-daily topical administration
Potent reduction of IOP

Question 24

Sites of drug action

Answer 24

uveoscleral outflow: prostaglandin agonists

Trebecular outflow: muscarinic agonists

Aqueous humor inflow: beta blockers, alpha 2 AR agonists, CAIs

Question 25

A 55-year-old woman has just been diagnosed with chronic open-angle glaucoma, and you conclude that drug therapy is indicated. She also tends to be tachycardic. Notes written by her family practice physician indicate that she has Stage 2 essential hypertension. Which one of the following drugs would be the most rationale choice for this woman? ``` Captopril Carteolol Diltiazem Hydrochlorothiazide Verapamil ```

Answer 25

Carteolol- beta blocker

Question 26

Beta-blockers

Answer 26

Non-selective (β1 and β2): Timolol, levobunolol, metipranolol, and carteolol β1-selective: Betaxolol (less efficacious than non-selective agents because the β receptors in the eye are largely of the β2 subtype) Twice daily dosing; fewer ocular side effects Systemic distribution may cause serious adverse effects Asthma, COPD, and some cardiac dysrhythmias are relative contraindications

Question 27

α-Adrenergic Agonists

Answer 27

α2-selective: apraclonidine, brimonidine Nonselective: epinephrine, dipivefrin (prodrug) Common adverse effects - Stinging, burning, blurring, or other discomfort in the eye - Dry mouth, headaches, and increased blood pressure Drug interactions - Antidepressants may alter metabolism

Question 28

A patient presents with chronic open-angle glaucoma. What “renal” drug, or a drug in the same chemical and pharmacologic class, might be prescribed as an adjunct to lower intraocular pressure and help manage this condition? ``` Acetazolamide Amiloride Furosemide Spironolactone Triamterene ```

Answer 28

Acetazolamide - carbonic anhydrase inhibitor not used a ton in HTN or glaucoma but is decent for both things at the same time

Question 29

Carbonic Anhydrase Inhibitors

Answer 29

Topical: dorzolamide, brinzolamide Oral: acetazolamide, methazolamide Frequent dosing; topical agents are less effective than other pharmacologic therapies Side effects - Topical: stinging, redness, dry eyes, and blurred vision - Oral: malaise, fatigue, depression, paresthesias, and nephrolithiasis

Question 30

Cholinomimetics

Answer 30

Muscarinic agonists: pilocarpine, carbachol AChE inhibitors: echothiophate Previously 1st line therapy Frequent dosing Side effects - Visual blurring from induced myopia - Fixed, small pupils - Can promote retinal tears - AChE inhibitors can promote cataract formation

Question 31

A patient has mild cutaneous and systemic manifestations of a seasonal allergic response. Before you prescribe a short course of diphenhydramine for symptom relief, you should realize that this drug has a mechanism of action resembling, causes many side effects similar to, and shares many contraindications, that apply to an “autonomic” drug, with which you should be very familiar. What is that drug? ``` Atropine Bethanecol Norepinephrine Phentolamine Physostigmine Propranolol ```

Answer 31

Atropine

Question 32

Drugs Contraindicated in Angle-Closure Glaucoma

Answer 32

Antimuscarinics Some antihistamines α1-adrenergic agonists

Question 33

Medical Marijuana for Glaucoma

Answer 33

``` Pros Lowers IOP (unknown mechanism) ``` Cons Short duration of action Altered mood and mental capacity Adverse effects include lung and brain damage Systemic hypotension could complicate vision loss Lack of quality control