Medications That Can Harm Glaucoma Patients
Chat Highlights
August 23, 2006

On Wednesday, August 23, 2006, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Medications That Can Harm Glaucoma Patients."

Moderator:  Welcome back to chat, Dr. Wilson.  Tonight we would like to learn more about medications that can harm glaucoma patients. Which are the worst?

Dr. Rick Wilson:   Diamox or Neptazane, oral carbonic anhydrase inhibitors (CAI), can have the worst side effects, but are rarely used now.  The worst side effect, aplastic anemia, was rare. The bone marrow was suppressed, and up to 50% of patients died of anemia.  That was in spite of the best that medicine had to offer.

P:   I was taking Neptazane for years when I was diagnosed as having a spastic colon.  Finally, I stopped taking Neptazane and the problem stopped.

Dr. Rick Wilson:  Neptazane can cause gas and diarrhea in susceptible patients.  Other side effects were loss of weight, often due to loss of taste, depression that could be severe, and loss of potassium which, in conjunction with heart drugs, causes serious rhythm problems of the heart.

The beta blockers cause the second-most serious problems, with a tendency for the elderly to fall, and exacerbation of asthma and emphysema.

P:   Is there any one class of drugs a glaucoma patient or glaucoma suspect should avoid?

Dr. Rick Wilson:  Topical or systemic steroids are the one medication of which glaucoma suspects with open angles need to be aware.  Topical or systemic steroids can cause an increase in IOP (intraocular pressure) that may take several months to recede.  The new treatment for swelling of the retina is a steroid injection into the back cavity of the eye.  That can cause dramatic rises in IOP.

P:   Are there medications that should be avoided by glaucoma patients and glaucoma suspects?

Dr. Rick Wilson:  Glaucoma suspects with narrow angles need to avoid any medication like ephedrine or scopolamine patches that could enlarge the pupil.  Those medications are labeled not to be used with glaucoma, but the warnings apply only to patients with narrow and occludable angles that might go into an angle-closure attack.

P:   Are there any medications used for psychological problems that can harm a glaucoma patient or glaucoma suspect?

Dr. Rick Wilson:  Only those that dilate the pupil in patients with occludable angles.

P:   How about medication for anti-bowel spasm?

Dr. Rick Wilson:  Only those that dilate the pupil, which are clearly marked with warnings.

P:   Are there any types of high blood pressure medications that are risky for glaucoma patients?

Dr. Rick Wilson:  That is a special issue.  Patients with glaucoma seem to be protected early in the course of hypertension because the higher blood pressure pushes blood into the eye to the optic nerve against a higher IOP.  However, if the blood pressure stays up, changes happen to the blood vessels in response to the high blood pressure that reduces flow to the optic nerve.  Then, if a doctor adds medicines to combat hypertension that lowers the blood pressure, the blood pressure can drop too low and blood flow to the eye will be compromised.

There is also the "white coat" hypertension, when patients only have high blood pressure when they are nervous in the doctor's office.  When such patients are given medicines to lower blood pressure that is normal most of the time, it ends up too low to pump blood into the eye against the eye pressure.

P:   It sounds as if glaucoma patients should guard against hypertension while they can.

Dr. Rick Wilson:  Yes, I think so.  Exercise and weight loss are cornerstones to preventing and treating hypertension.

P:   I have had trabeculectomies.  Do the glaucoma warnings on medications apply to me?

Dr. Rick Wilson:  Not if your trabeculectomies are working.  You would even be protected, to a large extent, from oral or topical steroids.

P:   How low would blood pressure have to be to compromise blood flow to the eye?

Dr. Rick Wilson:  That varies among individuals, depending upon whether they have other "co-morbidities," such as atherosclerosis of an irregular or slow heart rate.  I worry about patients who have blood pressures like 100/65 mm Hg during the day, because they often have pressures of 88/55 mm Hg at night.

P:   My pharmacist said not to take aspirin with Xalatan and Timoptic.  He advised Tylenol. Is that correct?

Dr. Rick Wilson:  I am not sure why he said that.  If you could call him and find out his reasoning and report back to us, he may know something I don't.

On the other hand, some Europeans feel that one of the possible problems with normal-tension glaucoma is an excessive stickiness to the platelets in the blood stream, which is usually treated with aspirin.  I have hundreds of patients on Xalatan and timolol who are also on aspirin.

P:   Are topical corticosteroids more likely to cause elevated intraocular pressure in people with pre-existing primary open-angle glaucoma?

Dr. Rick Wilson:  Yes, but they can do so in those patients with no hint of glaucoma who have a genetic predisposition to steroid responsiveness.

P:   Is there a racial difference for steroid-responsive intraocular pressure?

Dr. Rick Wilson:  Since African Americans and Hispanics of native American descent have a higher prevalence of glaucoma, one would think they have a higher steroid responsive rate as well.  However, Doug Rhee has found no racial predilection exists for steroid-responsive glaucoma. (http://www.emedicine.com/oph/topic124.htm)

P:   What is a steroid responder?  Is it common for people to be steroid responders?

Dr. Rick Wilson:  When subjects were given a potent steroid, dexamethasone, 4 times a day for 6 weeks, 5% had a rise in IOP of 15 mm Hg or more, 30% had a rise of 5 to 14 mm and 65% had a rise less than 5 mm.  However, with continued use of topical steroids, at least 50% of the population will get a serious IOP rise over time.

P:   Can Klonopin (clonazepam) be harmful for glaucoma patients?

Dr. Rick Wilson:  I don't know of any definite side effects specific for glaucoma. It is important for patients to realize that most medications have a risk-benefit ratio.  All medications have side effects.  Aspirin has prolonged and saved thousands of lives, but has caused a few people to bleed to death from stomach erosions.

I take Vioxx because it is the one medication that keeps me functioning.  The fact that it was taken off the market is criminal, because there are so many people like me with no heart history that should have been allowed to make the decision after talking with their doctors about whether or not to use it (the risk-benefit ratio).  After running out of Vioxx, I need to have my knees replaced.

P:   My doctor has prescribed Alphagan twice a day, but my eyes are red and bloodshot all the time. Is there a good alternative?

Dr. Rick Wilson:  That depends on what other medications you are taking.  If your eyes are red and bloodshot all the time, you are likely allergic to it and should stop it.  The effect also only lasts eight hours, so unless you are on another medicine to slow the washout of the Alphagan from the eye, you need to be taking it as close to three times a day as possible.

There are three other types of medications in widespread use for glaucoma: the prostaglandins, the beta-blockers, and the topical carbonic anhydrase inhibitors.

Moderator: Thank you. Dr. Wilson.  Next Wednesday evening, patients will be asking you general questions about glaucoma.

Dr. Rick Wilson:  See you then. Good night, everyone.

On September 6, Dr. Wilson discussed "Low Vision Aids" in the Chat room. Click here for highlights of that meeting.

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