Lec.10: Prostaglandin Analogs

Question 1

list the common prostaglandin drugs.

Answer 1

latanoprost, travoprost, bimatoprost and tafluprost

Question 2

what enzymes are crucial to converting prostaglandins from their prodrug form?

Answer 2

esterases

Question 3

once prostaglandins are activated by the body, what receptors do they act on?

Answer 3

F2alpha receptors on ciliary body

Question 4

name the ester prodrugs.

Answer 4

latanoprost, travoprost and unoprostone

Question 5

what type of prostaglandin is bimatoprost considered?

Answer 5

prostamide (nitrogen attached to carbonyl group)

Question 6

what is the mechanism of action for prostaglandin drugs?

Answer 6

increase outflow through uveoscleral pathway

Question 7

what class of glaucoma drugs are considered to by first line therapy?

Answer 7

prostaglandins

Question 8

what are the indications for prostaglandins?

Answer 8

POAG, NTG, PDS, XF and chronic angle closure glaucoma

Question 9

what are the contraindications for PGs?

Answer 9

uveitic glaucoma (inflammation), pediatric glaucoma, allergy to drug and pregnancy

Question 10

which PG analog has an association to cystoid macular edema?

Answer 10

latanoprost

Question 11

how long prior to surgery should PG medication be discontinued?

Answer 11

1 month

Question 12

what is the best time for patients to take PG medication?

Answer 12

evening

Question 13

what are the side effects of PG medications?

Answer 13

conjunctival hyperemia, iris color change, eyelash change, skin pigmentation and deepening of upper eye lid sulcus

Question 14

list the drugs in order of severity of conjunctival hyperemia?

Answer 14

brimatoprost>travoprost>latanoprost

Question 15

what percentage of PG users develop some sort of iris color change?

Answer 15

30-40%

Question 16

what is the reason for a change in iris color?

Answer 16

increase in melanin content (permanent change)

Question 17

what is a side-effect of excess drops around the eyelash and adnexa area?

Answer 17

increase in eyelash length and skin pigment change

Question 18

how long should patient keep their eyes closed when a PG drop is applied?

Answer 18

5 minutes

Question 19

how long should drops be spaced apart?

Answer 19

15 minutes

Question 20

what popular preservative may be linked to CME (cystoid macular edema)?

Answer 20

benzalkonium chloride (BAK)

Question 21

in general why do PG’s have low systemic side effects?

Answer 21

half-life of only 17 minutes in human plasma

Question 22

what preservative will form a precipitate when mixed with latanoprost?

Answer 22

thimerasol (found in CL solution)

Question 23

how much does latanoprost reduce mean diurnal IOP?

Answer 23

32%

Question 24

are PG’s better than timolol in african americans?

Answer 24

yes

Question 25

why are PG's not as effective in patients with pigment?

Answer 25

drug is absorbed by pigment and not distributed to the aq humor as effectively

Question 26

what is the additional drop in IOP if a beta blocker is prescribed alongside latanoprost?

Answer 26

14%

Question 27

how do cholinergic agonist like pilocarpine act?

Answer 27

act by increasing trabecular outflow facility

Question 28

is adding pilocarpine to PG a good idea?

Answer 28

no

Question 29

according to the FDA what is the problem with combination of PG's?

Answer 29

they must produce an additional IOP decrease of 20%

Question 30

is unoprostone a PG?

Answer 30

no (but it once was considered to be)

Question 31

how does unoprostone work?

Answer 31

works more on the trabecular outflow than the uveoscleral outflow