Medications
Chat Highlights
August 20, 2003
Norma Devine, Editor
On Wednesday, August 20, 2003,
Dr.
Rick Wilson, a glaucoma specialist at Wills, and the glaucoma
chat group discussed "Medications."
Moderator: Dr. Wilson,
would you like to start by talking about classes of glaucoma medications?
Dr. Rick Wilson: There are
five classes of topical medications.
- Beta-blockers decrease the amount of fluid the eye makes.
Timoptic is an example.
- Adrenergic medications [now consist mainly of brimonidine
(Alphagan)], which decrease fluid production, but also increase
flow out of the eye.
- Prostaglandins are now the most powerful and popular medications.
They help fluid leave the eye through the muscle in the eye
that does the focusing. Xalatan, Lumigan, Travatan, and
Rescula are the meds in this class.
- Carbonic anhydrase inhibitors decrease the amount of fluid
the eye makes. Examples are Trusopt and Azopt.
- The final class is miotics, now mainly pilocarpine, which
makes the pupil small, pulling on the drain (trabecular meshwork),
which is on the other side of the iris. Miotics mechanically
open the drain and help fluid escape from the eye.
P: When do side effects
become a factor in stopping a med? I have many side effects from
timolol, but my doctor keeps me on it.
Dr. Rick Wilson: If the side
effects are really changing the quality of your life, then they
should be stopped. Usually a doctor would change medication
causing side effects if there was a good alternative available.
P: Are doctors switching
patients from Xalatan to Lumigan and Travatan because of formulary
changes, lower cost, or better IOP lowering?
Dr. Rick Wilson: In a large,
well-run study, there seemed to be a slight but discernable lower
IOP (intraocular pressure) with Lumigan than with Travatan or
Xalatan. But Lumigan had the most side effects. Allergan,
which makes Lumigan, is quite aggressive about enticing pharmacy
plans to give exclusive prostaglandin status to their product.
P: Recently I read
something about contact lenses impregnated with glaucoma medications.
Can you expound on that?
Dr. Rick Wilson: There has
been experimentation for many years with liposomes and polymers
that could be used to make the contact lens, or a form-fitting
rod to fit under the lower lid, which would absorb a medication
and release it slowly over time. That would allow one application
to last for a week or more.
P: I have been using
Alphagan P and developed red eyes about three weeks ago.
My ophthalmologist said I have allergic conjunctivitis and prescribed
Patanol. Is red eye common with Alphagan?
Dr. Rick Wilson: If you have
follicles (bumps) under the lids, then you have a chronic allergy
and you should change medications.
P: Are some medications
avoided after combined surgery?
Dr. Rick Wilson: I use prostaglandins
and pilocarpine last in patients who have a bleb, as these two
meds cause more inflammation. Other doctors, however, do
not and that may just be my preference.
P: Could you explain
more about how the prostaglandins work on the focusing muscle?
Dr. Rick Wilson: They seem
to dissolve some of the cement substance between the muscle bundles.
Aqueous fluid can then flow among the muscle bundles and
be absorbed into the blood stream outside the eye.
P: When the cement
substance between the muscle bundles is dissolved, does that have
any effect on side vision?
Dr. Rick Wilson: No, we can't
find any.
P: Is the FDA expected
to approve Xalcom, a combination of Xalatan and the beta blocker
timolol?
Dr. Rick Wilson: Not that
I have heard. The FDA asked Pharmacia (now Pfizer) to redo
the study showing effectiveness, because timolol only seemed to
add 2 mm Hg of pressure lowering to the powerful action of Xalatan.
Xalcom is approved in Europe.
P: I'm using Alphagan
and Xalatan and can't wear my contacts any more because my eyes
are dry and burning.
Dr. Rick Wilson: Something
that has worked for my patients is a tablespoon full of flaxseed
oil, which can be purchased in health-food stores. The omega
3s in the oil help form a better tear film. It also lowers triglicerides
and cholesterol and may be helpful in arthritis. *
P: Has Allergan's Restatis
(cyclosporin) for dry eye syndome performed well in clinical practice?
Has there been a high incidence of corneal staining?
Dr. Rick Wilson: Restasis
is starting to be used in very dry eyes and provides relief by
reversing some of the inflammatory effects of the medications.
It seems to improve corneal staining and tear consistency.
P: What is Restasis?
Would it be helpful in uveitic glaucoma to manage flare?
You mention it helps to counter the inflammatory effect
of some meds.
P: Is Restasis similar
to the cyclosporin drops used to treat my dog's dry eyes?
Wouldn't that be interesting if my doggie and I can use the same
formula for dry eyes?
Dr. Rick Wilson: Restasis
is a very weak cyclosporin, so weak that, to my knowledge, it
only affects the surface of the eye. It could be used for
uveitis systemically in a segment of the uveitic population.
P: Do you think that
beta-blockers and any other medications that reduce aqueous production
are, if not contraindicated, at least ill-advised in pigmentary
glaucoma?
Dr. Rick Wilson: No. I
usually use a prostaglandin first in that situation. I would
rather encourage fluid to leave the eye than to decrease the production
of fluid. But control of the IOP is foremost, so I would
use other medications if needed.
P: Can young people
develop resistance to glaucoma meds? I'm 27 years old and have
been using Cosopt and Alphagan for nine years. I've also
been using one of the prostaglandins for about four years.
I'm wondering how much longer they will control my pressure. It
has been going up and down a lot lately. I am also just
getting tired of using so many drops all the time!
Dr. Rick Wilson: The prostaglandins
don't show much in the way of long-term drift, like the timolol
in Cosopt. I haven't seen much on long- term effect with
Alphagan and Trusopt/Azopt.
P: Do you think that
vitamins containing lutein are beneficial for the eyes?
Dr. Rick Wilson: It seems
to help in the prevention of age-related macular degeneration
for the retina. I know of no effect on glaucoma.
P: Which is stronger,
Xalatan or Travatan?
Dr. Rick Wilson: Randomized
studies show them to be equal in strength. The difference
between those two prostaglandins and Lumigan in terms of lowering
IOP is usually a half mm Hg or less.
P: When 5-Fu is used
postoperatively, how long does it take to determine if it is effective?
I've only had two of the five shots, but my IOP is still 17 mm
Hg and it needs to be in the low or single digits.
Dr. Rick Wilson: With any
of the anti-scarring drugs, I like to wait till the acute healing
phase has passed (usually about three months) to get an idea of
the long-term success.
P: What is 5-FU?
Dr. Rick Wilson: 5-fluorouracil
is a weak cancer drug that stops rapidly dividing cells from dividing.
Usually cancer cells are growing the most rapidly in the
body, so they are targeted by the 5-FU. In the postoperative
eye, the cells healing the wound are the most rapidly dividing
cells, so they are targeted and less scar tissue is formed.
P: Does the facilitating
effect that naturally occurring prostaglandins seem to have on
tumor growth have any relevance? Specifically, is there
any rational cause for concern for those of us using topical prostaglandin
analogs?
Dr. Rick Wilson: Prostaglandins
are very quickly metabolized once they get into the blood stream.
So I doubt that they have much remote effect.
P: The literature I
read (about tumor growth and prostaglandins) was unrelated to
the eye, but my concern was specifically for the LOCAL effects,
i.e., in the eye.
Dr. Rick Wilson: Eye tumors
are quite rare. Unless you had an occult malignancy, I cannot
see the prostaglandins having much of an adverse effect as far
as tumors are concerned.
P: Is mitomycin C (MM-C)
ever given in shots like 5-FU, or it is only used during surgery?
Dr. Rick Wilson: It can be
given in shots at 0.2 mg/cc.
P: What is the most
profound drop you have seen with a single medication and how long
did it maintain that effectiveness?
Dr. Rick Wilson: The higher
the original IOP, the easier it is to get a large percentage drop.
I have seen drops of over 50% with the prostaglandins and
Cosopt (a combination drop consisting of timolol and dorzolamide).
The longest-lasting effect I've seen so far has been two years.
End of highlights for August 20, 2003.
[Postscript: Dr. Rick Wilson has asked
that the following information be added to the Chat Highlights.
"I started taking flaxseed oil and ground flaxseed for my
arthritis, for which it did nothing, but I found it abolished
my dry eyes, dropped my triglycerides an unbelievable 40%, and
lowered my total cholesterol 15%. Since I had many years of serum
lipid profiles before and now after the start of flax, it even
convinced my cardiologist, who is using it for his patients. This
experience has been replicated for most of my patients and even
some of my fellows who have tried it."
A patient sent Dr. Rick an interesting article, entitled "What's
the Scoop on Flaxseeds?," which appeared in "Health
Extra" on the Web site of the Cleveland Clinic. http://www.clevelandclinic.org/healthextra/]
On August 27, Dr. Werner discussed "Steroids and Glaucoma" in
the Chat room. Click here for highlights
of that meeting.
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