Betaxolol-unoprostone combination more effective than monotherapy

Combination more effective in maintaining visual fields and may benefit NTG patients.

LONDON — Combined betaxolol and unoprostone therapy might be more useful for glaucoma patients than unoprostone monotherapy, according to the results of a study conducted by Yuichiro Ohtake, MD, of the Department of Ophthalmology, Keio University School of Medicine in Tokyo.

The combination treatment is effective for maintaining visual fields, and researchers consider it to be more advantageous for normal tension glaucoma, he added.

He and fellow researchers Tomihiko Tanino, MD, and Yukihiko Mashima, MD, evaluated the effect and safety of combined therapy with topical 0.5% betaxolol (Betoptic, Alcon) and 0.12% isopropyl unoprostone (Rescula, CIBA Vision) compared to unoprostone monotherapy. [Editor’s note: This formulation of unoprostone is only available in Japan and Central and South America. The formulation available in the United States is 0.15%.]

Dr. Ohtake told Ocular Surgery News, “It is generally accepted that betaxolol and unoprostone are effective in maintaining visual fields in glaucoma patients mainly due to their improving ocular blood flow and neuroprotective action. Therefore, we confirm the clinical advantage of combined betaxolol and unoprostone therapy for preserving visual field and controlling intraocular pressure.”

Creating the study

To confirm the theory, the researchers studied the effect and safety of combined therapy with topical 0.5% betaxolol and 0.12% isopropyl unoprostone compared to unoprostone monotherapy for 12 months. Dr. Ohtake reported results in the poster presentation, “Effect and safety of combined therapy with Betaxolol and isopropyl unoprostone” at the European Glaucoma Society meeting.

Researchers enrolled 42 eyes of 26 patients. They matched eyes by age and stage of glaucomatous visual field defect.

“We especially evaluated the effects of retinal sensitivity on glaucoma patients, which were matched in the aging and the staging of glaucomatous visual field defect,” he said. In the study, 34 eyes of 42 subjects had normal tension glaucoma.

In the study, 13 patients received betaxolol and unoprostone, and the rest received unoprostone twice daily for 12 months. Researchers checked intraocular pressure (IOP), automated perimetry, blood pressure, heart rate and peak flow every 6 months.

All participants had undergone perimetry more than once before the study. Blood pressure, heart rate and peak flow were done every 6 months in each group. The mean value of three time measurements was used to define blood pressure and heart rate. The maximum value of three time measurements by mini-Wright Peak-flow Meter (Clement Clark Co.) was adopted for peak flow.

Either therapy works

Combined therapy patients had a mean age of 58.6 years, with a range of 27 to 76 years. Unoprostone patients had a mean age of 59.9 years, with a range of 30 to 78 years.

Either therapy significantly reduced IOP (P<0.005), Dr. Ohtake said. The average of mean deviation value significantly improved from –7.84 dB to –5.36 dB after 12 months with combined therapy (P<0.005), while there was no difference with unoprostone monotherapy, he said.

For visual field exams, eight of 21 eyes (38.1%) receiving combined therapy improved 2 dB or more on mean deviation. Six of 21 (28.6%) eyes on monotherapy improved 2 dB or more. None worsened with combined therapy, while three with monotherapy worsened.

“There were no significant changes in the cardiovascular and pulmonary functions with each therapy,” Dr. Ohtake said. “Thus, the combined therapy with betaxolol and unoprostone might be more useful than unoprostone monotherapy for glaucoma patients.”

Researchers have not drawn any conclusions about the long-term effects of combined therapy on visual fields.

“We have not yet elucidated the mode of mechanism of this visual field preservation,” Dr. Ohtake said. “We consider it might be resulting from additive effects of IOP reduction or blood flow improvement. We consider that neuroprotection and ocular blood flow improvement, rather than IOP reduction by additive effect of both drugs, would affect visual field preservation.”

Researchers will continue the study to evaluate the change in ocular blood flow after combined therapy.

For Your Information:

• Yuichiro Ohtake, MD, can be reached at the Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan; (81) 3-5363-3820; fax: (81) 3-3359-8302; e-mail: ohtake@dmb.med.keio.ac.jp.

References:

• Ohtake Y, Tanino T, Mashima Y. Effect and safety of combined therapy with Betaxolol and isopropyl unoprostone. Atarashii Gannka (Journal of Eye). 2000;17(5):687-690.