Topical Verapamil Inhibits Experimental Diabetic Cataracts
NEW YORK (Reuters Health) - Topical verapamil hydrochloride inhibits the progression of lens opacities in rats with streptozotocin-induced diabetes, according to a report in the January 2004 British Journal of Ophthalmology. Diffuse cortical opacities involved the paracentral area of 10 lenses (16.7%) of untreated rats, the authors report, compared with only 2 lenses (3.8%) of verapamil-treated rats.
High dose oral or subcutaneous administration of verapamil was previously shown to prevent diabetic or galactosemic cataract in rats, the authors explain, but such systemic administration would lead to unacceptable side effects in patients.
Dr. Armin Ettl from University of Innsbruck, Austria and colleagues tested the effects of thrice-daily administration of verapamil 0.2% eye drops (a treatment recently shown by them not to produce plasma drug levels that could lead to systemic side effects) on the progression of diabetic lens opacities in rats.
Four placebo-treated lenses, but none of the verapamil-treated lenses, developed complete corticonuclear cataract, the report indicates.
The turbidity and integrated density in verapamil-treated diabetic lenses were significantly lower than in placebo-treated lenses, the researchers note.
Blood glucose levels and slit lamp examinations did not differ between treated and untreated rats, the results indicate.
"We have demonstrated the effect of verapamil, but -up to now- cannot explain its exact mechanism of action," Dr. Ettl told Reuters Health. "Therefore, further investigations with similar compounds and also pure stereoisomers are needed to elucidate its pharmacological profile."
"Many aspects of the pathophysiology of diabetic cataracts (e.g., calcium overload in cortical lens opacities) resemble the changes in human senile cataract," Dr. Ettl said. "The drug should also be evaluated for its efficacy in senile cataract."
"Verapamil eye drops have been shown to be effective in glaucoma. Therefore," Dr. Ettl added, "verapamil eye drops may be advantageous in patients suffering from both diseases."
Source: Br J Ophthalmol 2004;88:44-47. [ Google search on this article ]