Ophthalmics

Question 1

What receptor is targeted by the ocular drugs acetylcholine, pilocarpine, carbachol, and echothiophate? Are they agonists or antagonists, and direct or indirect acting?

Answer 1

Muscarinic receptor; all are agonists: acetylcholine, pilocarpine, and carbachol are direct, echothiophate is indirect

Question 2

What are 2 therapeutic uses for acetylcholine, pilocarpine HCl, and carbachol in the eye? How do they work?

Answer 2

Reduce IOP in glaucoma and after cataract surgery; direct ACh agonists that cause pupillary constriction –> increased aqueous outflow

Question 3

What disorder does echothiophate iodide treat, and how does it work?

Answer 3

Glaucoma; indirect muscarinic agonist that irreversibly binds AChE (increased ACh –> pupillary constriction –> increased aqueous outflow)

Question 4

What side effects are associated with taking acetylcholine, pilocarpine HCl, carbachol, and echothiophate iodide?

Answer 4

muscarinic agonists cause SLUDGE (salivation, lacrimation, urination, diarrhea, GI irritation, emesis), and also bronchospasm

Question 5

What receptor is targeted by the ocular drugs atropine, scopolamine, and homatropine, and how do they affect that receptor?

Answer 5

Muscarinic receptor antagonists

Question 6

What receptor is targeted by the ocular drugs cyclopentolate and tropicamide, and how do they affect that receptor?

Answer 6

Muscarinic receptor antagonists

Question 7

What are 2 therapeutic uses for atropine, scopolamine homatropine, cyclopentolate, and tropicamide?

Answer 7

Induce cycloplegia and mydriasis (ciliary muscle paralysis and pupil dilation) for eye exams, and improve comfort during uveitis (active eye inflammation)

Question 8

Rank the 5 antimuscarinic agents in order from fastest to slowest recovery time.

Answer 8

Tropicamide (1/4 d) - cyclopentolate (1 d) - homatropine (1-3 d) - scopolamine (3-7 d) - atropine (7-12 d)

Question 9

What side effects are associated with taking anticholinergics / muscarinic antagonists?

Answer 9

Insomnia, photophobia, urinary retention, and neurologic abnormalities (or: “dry as a bone, blind as a bat, red as a beet, mad as a hatter”)

Question 10

Describe edrophonium: what kind of receptor does it affect, what is its mechanism of action, and what is its main therapeutic use?

Answer 10

Nicotinic (Nm) receptor agonist that works at the NMJ by destroying AChE. Used to diagnose myasthenia gravis

Question 11

What receptors are targeted by the ocular drugs epinephrine, dipivefrin, hydroxyamphetamine, and cocaine; are they agonists or antagonists; and are they direct or indirect?

Answer 11

Adrenergic receptors; agonists; ephinephrine and its prodrug dipivefrin are direct while hydroxyamphetamine and cocaine are indirect

Question 12

Which sympathetic agonist causes dilation of episcleral vessels in order to increase aqueous outflow? What ocular disease is it used to treat?

Answer 12

Epinephrine; glaucoma

Question 13

Which sympathetic agonist prevents the reuptake of NE?

Answer 13

Cocaine

Question 14

What sympathetic agonist is used to differentiate 1st and 2nd order neuron dysfunction from 3rd order neuron dysfunction in Horner’s syndrome, and how does it do so?

Answer 14

Hydroxyamphetamine. It causes NE release: if pupillary dilation occurs, the 3rd order neuron is intact, so the problem lies in a 1st or 2nd order neuron (more dangerous)

Question 15

Which sympathetic agonist is a prodrug of epinephrine?

Answer 15

Dipivefrin

Question 16

What receptors are targeted by the ocular drugs clonidine, apraclonidine, phenylephrine, and brimonidine tartrate, and are they agonists or antagonists?

Answer 16

Alpha adrenergic receptor agonists (phenylephrine targets α1, clonidine and brimonidine target α2, apraclonidine is nonspecific)

Question 17

Which alpha specific sympathetic agonist is an amino derivative of clonidine that does not cross the BBB, and how does this alter its effect compared to clonidine?

Answer 17

Apraclonidine, allows it to decrease IOP without greatly affecting systemic blood pressure (in contrast, clonidine lowers IOP through CNS effects)

Question 18

Which sympathetic agonist mimics NE? What effect does it have?

Answer 18

Phenylephrine (except that it is α1 specific); pupil dilation

Question 19

Which 2 ocular drugs can cause side effects of extrasystoles, palpitation, hypertension, myocardial infarction, trembling, paleness, and sweating?

Answer 19

Epinephrine and phenylephrine

Question 20

How does brimonidine tartrate act on the eye?

Answer 20

α2 agonism suppresses production of aqueous humor, which decreases IOP

Question 21

Give 2 situations where brimonidine tartrate is contraindicated.

Answer 21

Should not be used with follicular conjunctivitis or with MAOIs

Question 22

What receptors are targeted by the ocular drugs dapiprazole and tamsulosin, and are they agonists or antagonists?

Answer 22

Dapiprazole = non-specific α antagonist 
Tamsulosin = α1 specific antagonist

Question 23

Which sympathetic antagonist, no longer widely available, reverses the pupillary dilation effects of tropicamide and phenylephrine? How does it do so?

Answer 23

Dapiprazole, it blocks α adrenergic receptors in the smooth dilator muscle of the iris

Question 24

What alpha antagonist is mainly used to treat prostatic hypertrophy? How can it affect the eye?

Answer 24

Tamsulosin (α1 specific blocker); it prevents pupil dilation –> makes cataract surgery more difficult

Question 25

What receptors are targeted by the ocular drugs timolol, levobunolol, metipranolol, carteolol, and betaxolol, are they agonists or antagonists, and what are they all used to treat?

Answer 25

Beta adrenergic antagonists / β-blockers (betaxolol is β1 specific, levobunolol is β2 specific, the rest are nonspecific); all are used to treat glaucoma

Question 26

What glaucoma agent is contraindicated in patients with CHF or asthma?

Answer 26

Timolol

Question 27

What mechanism do all the beta-blockers employ to treat glaucoma?

Answer 27

They reduce IOP by suppressing production of aqueous humor at the ciliary process

Question 28

Which beta-blocker “doesn’t follow the rules” because it lacks significant intrinsic sympathomimetic activity?

Answer 28

Metipranolol (it has only weak effects on membrane stabilization and myocardial depression)

Question 29

What side effect may result from long-term bradycardia secondary to timolol use?

Answer 29

Tachyphylaxis (acute decrease in response to a drug)

Question 30

What receptors are targeted by the ocular drugs latanoprast, travoprost, bimatoprost and unoprostone isopryl, and are they agonists or antagonists?

Answer 30

Prostaglandin receptor agonists

Question 31

What mechanism do the prostaglandin analogs use to treat glaucoma?

Answer 31

Increase outflow of aqueous humor

Question 32

List 2 common side effects seen with the prostaglandin analog drugs, and 2 contraindications for their use.

Answer 32

Eyelash growth and change in iris color; contraindicated in patients with cystoid macular edema or herpes

Question 33

What is unique about the effectiveness of travoprost and unoprostone isopryl in treating glaucoma?

Answer 33

Travoprost is more effective in African Americans; unoprostone isopryl is the least effective overall

Question 34

Name the calcium channel blocker drug that is used to treat glaucoma. How does it work?

Answer 34

Nifedipine; increases ocular perfusion at the nerve head (does not act at the ciliary body or trabecular meshwork)

Question 35

What proteins are inhibited by the ocular drugs dorzolamide HCl, brinzolamide, and acetazolamide? How are these drugs administered?

Answer 35

Carbonic anhydrase inhibitors; dorzolamide HCl and brinzolamide are topical, acetazolamide is oral

Question 36

What disease do the carbonic anhydrase inhibitors treat, and how do they work?

Answer 36

Glaucoma; they reduce aqueous humor production by interfering with the Na/K ATPase pump

Question 37

What side effects are seen with the two topical carbonic anhydrase inhibitors?

Answer 37

Red eyes and lid allergies (but far less systemic side effects than for acetazolamide)

Question 38

What ocular drug is contraindicated in patients with sulfonamide allergies?

Answer 38

Dorzolamide HCl