Stay on top of new systemic diabetes therapy to help monitor ocular conditions

Issue: November 2000

In the wake of the Food and Drug Administration (FDA) banning Rezulin (troglitazone, Parke-Davis/Warner-Lambert), several other drugs have emerged as viable alternatives for systemic treatment of diabetes. Optometrists should be aware of these treatments, as well as know what to look for when monitoring diabetics and when to refer them to appropriate specialists.

When monitoring patients for diabetic retinopathy, William Jones, OD, in private group practice in Albuquerque, N.M., said he looks for several types of diabetic eye disease. “It can be in the form of neovascularization of the iris or neovascular glaucoma to either nonproliferative or proliferative retinopathy,” he said. “I also look for vitreous hemorrhages.”

When to refer

In deciding whether to refer the patient to a vitreoretinal specialist, Dr. Jones advised looking for two conditions: diabetic macular edema and neovascularization.

“Be sure to watch for clinically significant diabetic macular edema: retinal edema involving the macula, a patch of edema 1 disc diameter from the fovea and 1 disc diameter in area or hard exudates within 500 µm associated with retinal edema” he said. “Neovascularization of the disc, retina or even the iris would certainly warrant a referral to a retinal specialist.”

If neovascularization is greater than one half of the disc area or accompanied by vitreous hemorrhage, or if neovascularization elsewhere is greater than one half disc area and vitreous or preretinal bleed exists, then this would require panretinal photocoagulation, Dr. Jones explained. “Clinically significant diabetic macular edema requires fluorescein angiography and focal laser treatment to the areas of involvement,” he said.

Another reason to refer a patient to a retinologist, Dr. Jones said, would be a vitreous hemorrhage, “because, in most cases, neovascularization of the retina or optic nerve is causing the hemorrhaging.”

When an optometrist finds any type of diabetic eye disease, usually retinopathy, in a patient who does not have a primary care physician or an internist, Dr. Jones said you should have patients seek out someone to monitor and treat their condition. “If the patient does have a physician, I make sure he or she notifies that physician of diabetic problems with his or her eyes,” Dr. Jones said.

What’s new in diabetes treatment?

Glitazones are a new class of drugs used to treat type 2 diabetes by sensitizing the body to insulin. The FDA removed Rezulin, one of the most promising glitazone drugs, from the market in March after it was linked to at least 63 deaths from liver poisoning. However, two newer glitazone drugs have filled in the gap, according to Paul S. Jellinger, MD, FACE, president of the American Association of Clinical Endocrinologists.

“Actos (pioglitazone, Takeda/Eli Lilly) and Avandia (rosiglitazone, Smith Kline Beecham) represent new adjuncts to our armamentarium,” he told Primary Care Optometry News. “They treat insulin resistance directly by affecting cellular mechanisms. They actually get into the cell where insulin has to work and they make the cell more responsive to the insulin, in effect, reversing insulin resistance.”

Although these two drugs act in the same manner as Rezulin, there are some differences in the length of time the drug resides in the liver that may be the reason they appear safer, Dr. Jellinger said.

A newly approved combination drug called Glucovance (Bristol-Myers Squibb) is also an effective alternative for treating diabetes, Dr. Jellinger said. “It is not a new drug,” he said. “Rather, it is a newly available combination of two existing drugs, glucophage and glyburide. One of the components of the combination is an insulin sensitizer. It is not in the glitazone class, but it achieves nearly the same result by a different mechanism. The other component of the combination drug is a sulfonyurea, which has been available to physicians for close to 50 years, Dr. Jellinger said.

Stimulating insulin release

Starlix (nateglinide), manufactured by Novartis, is a new oral agent in development that may be made available early next year, according to Dr. Jellinger. “It works to stimulate insulin release as the patient eats,” he said. “There is no drug currently available that works exactly like that.”

For treating insulin-dependent type 1 diabetes, new types of insulin may soon become available. “Only about 25% of type 2 diabetics require insulin, but all type 1 diabetics require it,” Dr. Jellinger said. “This new insulin will be called Glargine (Hoechst Marion Roussel), and it is a true basal, 24-hour insulin. You give one dose a day, and it provides a very nice background basal rate.” Glargine is expected to be available in the next few months.

Insulin pumps

The use of insulin pumps to treat type 1 diabetes is increasing tremendously, Dr. Jellinger said, and it is an extremely effective treatment. “The pumps are for people who have absolute insulin deficiency and require two or three injections of insulin a day,” he said. “Instead of the injections, they wear a pump that delivers the insulin continuously.”

He explained that the wearer changes the syringe and the tubing about every 2 to 3 days. “Before each meal, the patient just tells the pump how much insulin to deliver. Between meals, it delivers a little bit each hour, so it’s very effective,” he said.

Dr. Jellinger explained that the patient wears the pump virtually 24 hours a day, taking it off for short periods of time to shower or during other activities. “Using the pump tends to reduce swings in blood sugar, stabilizing the diabetes to a significant degree. It doesn’t make it perfect, but it stabilizes it,” he said.

For Your Information:

William Jones, OD, FAAO, is in private group practice and is a member of the Editorial Board of Primary Care Optometry News. He may be reached at 1828 Conestoga, SE, Albuquerque, NM 87123; (505) 265-1711, ext. 4141; fax: (505) 247-2153; e-mail: wm_jones@msn.com. Dr. Jones has no direct financial interest in any of the products mentioned in this article, nor is he a paid consultant for any companies mentioned.

Paul S. Jellinger, MD, FACE, is president of the American Association of Clinical Endocrinologists. He can be reached at 1000 Riverside Ave., Ste. 205, Jacksonville, FL 32204; (954) 963-7191, ext. 233; fax: (954) 963-6213; e-mail: pjellin@pol.net. Dr. Jellinger is on the Speakers Bureau for all of the companies mentioned in this article. He has no direct financial interest in any products mentioned in this article, nor is he a paid consultant for any companies mentioned.