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Medical Edge Newspaper Column from Mayo Clinic

DYE USED IN EYE THERAPY COULD CAUSE UNDUE STRESS TO IMPAIRED LIVER

DEAR MAYO CLINIC: I am planning to have photodynamic therapy to stop fluid leakage around my retina, but am skeptical about it because of lack of information. Have there been any studies on side effects — long- and short-term — of Visudyne on the rest of the body, such as problems with liver, kidneys, etc.? How long has this drug been used? — Sarasota, Fla.

ANSWER: The treatment you ask about, ocular photodynamic therapy, is increasingly used to treat a variety of neovascular membrane conditions in the eye. But because you don’t mention the diagnosis you’ve received, let’s assume you have age-related macular degeneration. OPT has rapidly replaced thermal laser photocoagulation as the preferred treatment for the kind of leakage you describe.

In age-related macular degeneration, leaks occur when blood vessels grow between the central portion of the retina, called the macula, and its supporting layer of choroid tissue. These vessels can leak blood or plasma. When that happens, the leaking fluid damages the cells responsible for central (“straight-ahead”) vision and impairs sight. If left untreated, the condition may lead to scarring and considerable visual impairment.

The treatment you ask about seals off the leaking blood vessels. It consists of a 10-minute minute intravenous infusion of Visudyne, a photosensitive dye, followed by an 83-second pulse of low-intensity infrared laser delivered through a contact lens to the area of affected retina.

OPT was approved by the Food and Drug Administration for general use in early 2000, though studies establishing its safety and efficacy began enrolling patients in 1996. During the six years of follow-up after the original investigational OPT treatment series, there have been no reports of long-term complications to the organs you mentioned, the liver and kidney.

However, large studies have reported head- and eye-complication rates as high as 40 percent — though most of these complications have been transient headaches and visual disturbances. Most also probably have nothing to do with Visudyne.

Here’s what you should know about Visudyne: It is rapidly distributed throughout all of the body’s tissues, including the skin — which puts patients’ exposed skin at high risk of sunburn following infusion. Patients receiving Visudyne are instructed to wear long sleeves, pants and a wide-brimmed hat for the postoperative trip home, and must remain indoors, out of direct sunlight and away from halogen lights for up to five days.

Your doctor also needs to make sure that you have healthy liver function. The liver eliminates Visudyne from the body for 24 hours after the procedure. Even though there have been no reports of injury to normal livers, patients with impaired liver function should not receive the extra stress of having to clear Visudyne from the body. In addition, patients with known sensitivity to porphyrin compounds should not receive Visudyne. If you have not yet discussed these issues with your doctor, you need to raise them.

Finally, you may need to plan for more than one treatment. That’s because the low laser power delivered by OPT is designed to cause as little damage as possible to retinal and choroidal tissues surrounding the neovascular membranes. Therefore, most blood vessels are not completely closed by a single treatment. Though some patients respond very well to a single treatment, most patients require an average of three to five treatments spaced at three-month intervals.

Michael W. Stewart, M.D.; Ophthalmology; Mayo Clinic, Jacksonville, Fla.

Additional Resources:

What is Oculuar Photodynamic Therapy?
Appointment Information
Information on Macular Degeneration

READERS: If you smoke — and are scheduled for surgery for any reason — it’s a good time to quit.

That’s the finding of a Mayo Clinic study funded by the Minnesota Partnership for Action Against Tobacco, which compared stress levels before and after surgery among 141 smokers and 150 nonsmokers.

For any surgery, smokers must stop smoking — at least for a while — because healthcare facilities prohibit tobacco use. Researchers found that smokers didn’t report any more increased stress than nonsmokers. Nicotine withdrawal symptoms weren’t significantly bothersome, either.

Researchers believe that since smokers have other things to worry about — their surgery and recovery — they don’t focus on the fact that they aren’t smoking.

Additional Resources:
Nicotine Dependence Center
Appointment Information
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Medical Edge from Mayo Clinic is an educational resource and doesn’t replace regular medical care. To e-mail a question, go to www.mayoclinic.org, or write: Medical Edge from Mayo Clinic, c/o TMS, 2225 Kenmore Ave., Suite 114, Buffalo, N.Y., 14207. For health information, visit www.mayoclinic.com.