Lecture 10 Prostaglandin analogs

Question 1

(T/F) PROstaglandin analogs (PG’s) are Pro-inflammatory PRO-drugs.

Answer 1

True. The PRO-inflammatory properties of PG’s make these not a good med to use for angle closure (remember: use ABC’s for angle closure). PRO-drugs are stored in their inactive form and become active via corneal enzymes (esterases).

Question 2

Of the following prostaglandin analogs, which is actually a prostamide?

a) latanoprost
b) travoprost
c) bimatoprost
d) tafluprost

Answer 2

c) bimatoprost. This has a similar configuration as the prostaglandins, however, it has an amide (nitrogen group) attached. Therefore, it a prostamide but acts very similar to a PG’s.

Question 3

Which of the following is the most commonly used PG?

a) latanoprost
b) travoprost
c) bimatoprost
d) tafluprost

Answer 3

a) latanoprost (Xalatan). This med shifted glaucoma therapy from a surgical specialty to a medical specialty.

Question 4

Which of the following is the most effective drug classification for lowering IOP

a) prostaglandin analogs
b) alpha-2 adrenergic agents (agonist)
c) beta-blockers
d) carbonic anhydrase inhibitors (CAI’s)

Answer 4

a) prostaglandin analogs

Question 5

Prostaglandins work on prostaglandin F2a receptors located where and how?

a) on the ciliary body to mainly increase outflow via the uveolscleral pathway.
b) In the trabecular meshwork to mainly increase aqueous outflow via conventional route
c) on the ciliary processes to decrease outflow

Answer 5

a) on the ciliary body to mainly increase outflow via the uveolscleral pathway. a small percentage will increase conventional outflow. PG’s do NOT reduce aqueous production

Question 6

Which one of the following is a prodrug but not a PG?

a) latanoprost
b) unoprostone
c) travoprost

Answer 6

b) unoprostone

Question 7

(T/F) PG’s reduce aqueous production

Answer 7

False, they only increase unconventional/uveoscleral outflow pathway.

Question 8

Which 2 are the 2 theories for the mechanism of action of PG’s?

a) inhibition of cAMP which decreases production of aqueous
b) They create pupillary miosis, stretching the iris, therefore allowing more aqueous to drain.
c) relaxation of the ciliary muscle and increase in ciliary body thickness
d) dilates spaces between ciliary muscle bundles in uveolscleral outflow pathway to increase outflow of aqueous via enzymes like collagenases and matrix-metalprotenases

Answer 8

c) relaxation of the ciliary muscle and increase in ciliary body thickness (PG’S)
d) dilates spaces between ciliary muscle bundles in uveolscleral outflow pathway to increase outflow of aqueous via enzymes like collagenases and matrix-metalprotenases (PG’S)

a) inhibition of cAMP which decreases production of aqueous (BETA-BLOCKERS)
b) They create pupillary miosis, stretching the iris, therefore allowing more aqueous to drain. (CHOLINERGICS)

Question 9

(T/F) PG’s are the 1st line therapy for most forms of glaucoma

Answer 9

True. PG’s lower IOP in POAG, NTG, PDS (pigment dispersion syndrome), XFS (exfoliation syndrome). caution with uveitic glaucoma, angle closure glaucoma or any other active inflammation (since PG’s are pro-inflammatory)(also PG’s are less effective in pediatric glaucoma)

Question 10

Which one of the following is NOT a contraindication for PG’s?

a) allergies to this drug
b) pregnant/nursing (PG’s are abortive meds and show up in milk)
c) sulpha allergies
d) pediatric-(less effective)
e) ocular inflammation (CME, iritis, herpes simplex keratitis, ocular surgeries)

Answer 10

c) sulpha allergies. This is a contraindication for CAI’s.

Question 11

Your pt is on latanoprost for his glaucoma. He will be getting cataract surgery soon. What is the protocol?

Answer 11

With PG’s, such as latanoprost, ocular inflammation is a contraindication. You will have pt stop using the PG for 1 month prior to surgery and for 1 month post-op (2 months total). In the meantime, put pt on a a-2 agonist, beta-blocker, or CAI

Question 12

How often should your pt use a PG?

a) BID
b) TID
c) QD
d) QID

Answer 12

c) QD in the evening. Helps prevent morning spike in pressure. Should not be used more than once daily. Also, since PG’s cause hyperemia its better to use before you go to bed so you do not have to be in public with red eyes.

Question 13

Which of the following is NOT a known side effect of prostaglandin analogs (PG’s)?

a) eyelash growth
b) skin pigmentation
c) sexual dysfunction
d) DUES (deepening of upper eyelid sulcus)
e) conjuctival hyperemia

Answer 13

c) sexual dysfunction. This is an adverse effect in OBB’s (ocular beta-blockers)

Conjunctival hyperemia (red eye) is the MAIN side effect of PG’s

Question 14

In theory, which of the following PG’s are in order from most likely to least likely in regards to causing conjunctival hyperemia (red eye)?

a) Brimatoprost, Travoprost, Latanoprost
b) Travoprost, Brimatoprost, Latanoprost
c) Latanoprost, Travoprost, Brimatoprost

Answer 14

a) Brimatoprost (most likely to cause hyperemia), Travoprost, Latanoprost (least likely)** acronym to help remember: BTL=Big Then Little**

Question 15

(T/F) Conjunctival hyperemia (red eye) is the MAIN side effect of PG’s

Answer 15

True

Question 16

What is Latisse used for?

Answer 16

It is a PG (Bimatoprost) that was rebranded for the cosmetic purpose of lengthening and thickening eyelashes. This is reversible, if you stop using then your lashes go back to normal.

Question 17

Name two major cosmetic concerns dealing with the use of PG’s.

Answer 17

1) Skin pigment color changes. It is important to wash off excess drops around the eye. This change is reversible
2) Iris color change. Incidence of 30%-40%. Increase in melanin content but not melanocytes. This change is irreversible. You may not want to give to a pt with blue eyes unless they do not care if they turn brown.

Question 18

You are writing an rx for Travoprost 0.004%, 2.5ml bottle, instill 1 gtt ou q pm. How many days will this bottle last?

a) 50 days
b) 25 days
c) 15 days
d) 10 days

Answer 18

“1 gtt ou q pm” means 1 drop in both eyes every evening. 1 ml equals 20 drops. 2.5ml equals 50 drops, 2 drops per day are used (one in each eye), therefore the bottle will last 25 days.

Question 19

(T/F) Some reports show an association of PG’s and CME’s (cystoid macular edema). Do not use with pt’s who have CME’s or are at risk for CME’s

Answer 19

True. However, they believe it may have been the preservative BAK (benzalkonium chloride) as the probably cause of CME.

Question 20

The risk of uveitis while taking PG’s is ______.

a) high
b) low
c) moderate
d) none of the above

Answer 20

b) low. a study showed 10 out of 198 showed some cells/flare.

Question 21

Which 2 are correct regarding PG’s?

a) metabolized by kidneys
b) metabolized by liver
c) eliminated by kidneys
d) eliminated by liver

Answer 21

b) metabolized by liver

c) eliminated by kidneys

Question 22

What is the half life (in human plasma) of PG’s?

a) 33 minutes
b) 7 minutes
c) 2 hours
d) 17 minutes

Answer 22

d) 17 minutes

Question 23

Which one of the following is a systemic side effect of PG’s?

a) alters lipid metabolism
b) can cause symptoms similar to that of hypoglycemia
c) sexual dysfunction
d) decreases blood pressure
e) PG’s do not have any known systemic side effects

Answer 23

d) PG’s do not have any known systemic side effects (beta-blockers can alter lipid metabolism, cause sexual dysfunction, decrease blood pressure, and mask symptoms of hypoglycemia in diabetic pts)

Question 24

(T/F) Always separate instillation of PG’s with eyedrops known to contain thimerasol by 5 minutes because mixing the 2 drops forms precipitates which prevent absorption.

Answer 24

true.

Question 25

Which one of the following is NOT a true statement?

a) FDA guidelines state that all glaucoma meds are to be compared to timolol.
b) When comparing PG’s to timolol, timolol is more efficient at lowering IOP
c) IF you want to add another glaucoma med to a PG, it would make sense to add a med that decreases aq. production since PG’s increase outflow.
d) PG’s are better than timolol in African americans

Answer 25

b) When comparing PG’s to timolol, timolol is more efficient at lowering IOP (PG’s are more efficient at lowering IOP than timolol)

Question 26

(T/F) With PG’s there is no loss of effect overtime

Answer 26

true

Question 27

(T/F) Adding an a-2 agonist, beta-blocker, or CAI to a PG provides an additional 15% drop in IOP

Answer 27

true (only adding the CAI dorzolamide was different, it gave an extra 24% drop). Adding a cholinergic to a PG only gives an additional 7% drop in IOP

Question 28

Which one of the following is a TRUE statement?

a) PG’s increase aq. outflow
b) Alpha-2 agonists, like Brimonidine, decrease aqueous production
c) Beta blockers decrease aqueous production
d) CAIs decrease aqueous production
e) Cholinergics, like pilocarpine, increase trabecular outflow by causing pupillary meiosis
f) All of the above are correct

Answer 28

f) All of the above are correct

Question 29

Which one of the following is NOT an advantage of a fixed combination drug?

a) better pt compliance
b) less expensive
c) less follow ups with the doctor
d) more convenient

Answer 29

c) less follow ups with the doctor

Question 30

(T/F) There are no PG containing combo drugs available in the US.

Answer 30

true. FDA requires at least a 20% additional drop in order to manufacture a combo. However there are non-PG containing combos.

Question 31

(T/F) A new combo drug called latanoprost bunod (LBN) will soon hit the market. Studies show it decreases IOP by 1mmHG more than Latanoprost alone.

Answer 31

True. The latanoprost acts in increasing uveoscleral outflow. The Bunod portion becomes a 1,4 butanediol and nitric oxide. The nitric oxide dilates TM and increases trabecular outflow.

Question 32

(T/F) Unoprostone (Resecula) was initially thought to be a prostaglandin. The side effects are similar to PG’s. It also improves trabecular outflow. There are no associated heart/lung issues.

Answer 32

True