Pros & Cons of Available Pressure-reducing Medications
Chat Highlights
May 17, 2006

On Wednesday, May 17, 2006, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Pros & Cons of Available Pressure-reducing Medications."

Moderator:  Tonight's topic is “Pros & Cons of Available Pressure-Reducing Medications”.  Dr. Wilson, do you want to start by discussing a particular class of medications first, such as prostaglandin analogs, beta-blockers, carbonic anhydrase inhibitors, miotics, or combination drugs?

Dr. Rick Wilson:    Does the group have any favorites they would like to discuss?

P:    I would like to know about Betoptic.

Dr. Rick Wilson:  Betoptic is a beta-blocker that is selective for the beta receptors mainly in the heart.  Therefore, it has little effect in the lungs, where blocking beta adrenergic tone can make asthma worse.  Betoptic, however, is a weak beta-blocker, so it also has only a slight effect on the heart.  Therefore, it is the safest beta-blocker, but is slightly weaker than the non-selective beta-blockers, such as timolol or levobunolol or cartelol, and has to be taken twice a day versus once a day for the others.

P:  I thought timolol was taken twice a day.  Is it taken only once now?

Dr. Rick Wilson:  In most people, especially if their irides (irises) are light-colored, once a day after six weeks of the loading dose is sufficient to maintain maximal IOP (intraocular pressure) lowering.

P:  When and why is atropine used?

Dr. Rick Wilson:  Atropine relaxes the sphincter muscle of the pupil and the muscles that work the lens in the eye.  It is used in an inflamed eye or after surgery to relax the eye. In patients with a shallow anterior segment (the space between the iris and the cornea), in some cases it is used to deepen the anterior chamber.

P:  What is Cosopt?

Dr. Rick Wilson:  Cosopt is a combination of a beta-blocker (timolol, Timoptic) and a carbonic anhydrase inhibitor (dorzolamide, Trusopt).  Therefore, it has the effect of two different medications, with one eyedrop twice a day.

P:  How about Xalatan?

Dr. Rick Wilson:  Xalatan is the most commonly used prostaglandin, though Travatan and Lumigan are gradually gaining market share.  Prostaglandin is a naturally occurring chemical in the body.  When it is introduced into the eye, it increases the flow of fluid between the muscle fibers of the ciliary body (the part of the eye that makes fluid and focuses the lens) and out of the eye.

Moderator:   What are the pros and cons of using Alphagan?

Dr. Rick Wilson:  Alphagan is slightly more powerful than Azopt orTrusopt, one to two hours after instillation, but it is slightly less powerful after eight hours.  If used alone, Alphagan should be instilled three times a day.  If Alphagan is used twice a day, the IOP rises to what it would be without medication 12 hours after instillation. It is not as powerful as a beta-blocker and significantly less powerful than a prostaglandin.  When added to two or three other medications, Alphagan works better than other medications in the same situation.  Side effects include allergies and a feeling of fatigue.

P:  Are the pros and cons of Lumigan similar to those of Xalatan and Travatan?

Dr. Rick Wilson:  Xalatan and Travatan are equally effective.  On average, Lumigan gives an additional one-half millimeter of mercury of effect, but in some people Lumigan has a significantly greater effect.  The increased lowering comes at the expense of redder eyes and even some eye ache.

P:  Do many people using Lumigan complain of fatigue and joint pain?

Dr. Rick Wilson:  Not many, but some complain of flu-like symptoms.

P:  I've read that the prostaglandin analogs enhance uveoscleral outflow by acting on ("restructuring") the collagenous matrix of the ciliary muscle bands -- or something to that effect.  To whatever extent that's actually the case, has anyone looked for any deleterious side effect on the collagenous vitreous, that is, more syneresis or other vitreous problems with prostaglandin use?

Dr. Rick Wilson:  Xalatan, the first of the prostaglandins, has been in use for over a decade all over the world, with very few ocular or systemic problems other than the ones we've already mentioned.  The other prostaglandins are similar, although Lumigan, with its stronger concentration, causes somewhat redder eyes and darkening of the skin around the eye.

P:  When you are assessing potential treatment, do you start first by analyzing the pros and cons of a class and then the specific drugs within that class?

Dr. Rick Wilson:  Yes.  Since Alphagan, Trusopt, and Azopt are three-times-per-day drops when used by themselves, and since almost everyone has trouble remembering to use a drop in the middle of the afternoon, we usually start with a beta blocker or prostaglandin.  Prostaglandins are not for everyone because they may darken the irides (iris) of patients with light, multicolored irides and may increase the inflammation in eyes that already have a slight inflammation.

P:  You didn't mention Rescula.  The manufacturer claims that Rescula acts differently from the other prostaglandin analogs.  It's also claimed to have neuroprotective effects.

Dr. Rick Wilson:  Unfortunately, the makers of Rescula were never able to gain sufficient market share to make their medication profitable.  You cannot get it in the U.S. anymore.

P:  Are there other unavailable medications besides Rescula?

Dr. Rick Wilson:  Yes, thymoxamine is a drug with the potential to help in pigmentary dispersion syndrome and pigmentary glaucoma.  Fortunately, there are not that many patients with these problems.  Unfortunately, there are not enough patients to justify the liability and manufacturing costs to make the medication.

P:  Aside from a drug's effectiveness, don't other factors, such as frequency of application, price, availability, insurance company preferences, and interactions with other drugs influence the doctor's decisions?

Dr. Rick Wilson:  Right you are.  All those factors come into play when the doctor makes a decision concerning which medication to start with or add. In more and more cases, insurance company formularies limit that choice to the drug for which they have obtained the best price.

P:  I saw a news snippet about how a single subconjunctival injection of Retaane lowered IOP dramatically for months, at least in the few people who used it. Have you heard anything about that?

Dr. Rick Wilson:  Nothing more than you have, it seems.  I have not seen a large-enough randomized study to be able to say anything definite about the medication.

P:  Side effects would go on the "con" side, but even so, individual physiology and preference may come into play.  For example, one person may not mind longer, thicker eyelashes, but those would be undesirable side effect for another person.

Dr. Rick Wilson:  I do have women taking a prostaglandin in one eye who want to use it in both eyes to obtain equally long and dark lashes.

P:  Are there any new medications on the horizon? How about pills or patches?

Dr. Rick Wilson:  Both Alcon and Allergan, as well as Pfizer, want to bring out medications with a prostaglandin and a beta blocker combined.  To my knowledge, they have not made it past the FDA, but the companies feel they are close.

P:  I was told that using Cosopt, Lumigan, and Alphagan will have long-term effects on my body.  What would the negative effects be, and how long would it take before they occurred?

Dr. Rick Wilson:  The use of those medications causes chronic allergic/inflammatory changes in the conjunctiva.  If there is not a frank allergy, the main problem with the use of those medications is the reduced effectiveness of glaucoma surgery, because of the increased inflammation and scarring they cause.  Beta blockers slow the heartbeat, an effect that gradually diminishes over the course of six months.

P:  Is there a certain length of time when long-term usage of those medications reduces the effectiveness of glaucoma surgery?

Dr. Rick Wilson:  No, it can happen in the first year or build up over many years.  It varies dramatically with each patient.

P:  As a glaucoma suspect, should I avoid sleeping pills?

Dr. Rick Wilson:  If you have normal blood pressure and nicely open angles in the front of the eye, then any medication except topical or oral steroids should not cause a real problem.  Most of the medications that carry warnings about use with glaucoma pertain to patients with narrow angles.  Patients with seriously narrow angles, however, have been diagnosed and usually have had a peripheral iridectomy (laser hole in the iris) to protect them from having an attack. People not yet diagnosed with glaucoma would not know to heed the warning.  Therefore, the warnings scare many people who are not affected by the problem at all, and don't reach the people who need the warnings.

P:  Since being diagnosed with glaucoma in January 2005, my son has tried many different glaucoma eyedrops.  Until his appointment this week, he was on Azopt and Lumigan.  His pressures were 20 mm Hg, and the doctor decided to change from Azopt to Cosopt.  I'm concerned that my son will run out of medications to try. Is my concern unfounded?

Dr. Rick Wilson:  No, it is not. We basically have only four major drug groups to treat glaucoma.  Pilocarpine is rarely used anymore.

Moderator:   Thank you, Dr. Wilson. Goodnight.

On May 24, Dr. Wilson discussed "Risk-benefit Ratio for Surgical Intervention" in the Chat room. Click here for highlights of that meeting.

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