Der Einfluß von Enalapril auf den intraokulären Druck: Widersprüchliche Pilotstudien?

Zusammenfassung

In einer unkontrollierten Pilotstudie an 26 Augen von 13 Probanden (acht normale, zwei glaukomverdächtige und 16 Glaukom-Augen) konnte durchschnittlich vier Stunden nach Einnahme einer Tablette Reniten (20 mg Enalapril) eine mittlere Drucksenkung von 20% festgestellt werden. In einer zweiten, doppelblind und „cross-over” durchgeführten Studie über zweimal sechs Wochen (täglich 2×10 mg Enalapril-Kapseln oder Plazebo-Kapseln) an fünf normotensiven Patienten konnte keine Senkung des Augendruckes gefunden werden. Auf dieses nur teilweise widersprüchliche Resultat wird eingegangen.

Summary

The effect of 20 mg orally administered Enalapril (Reniten TM) an angiotensin converting enzyme (ACE) inhibitor, on the intraocular pressure (IOP) of twenty-six eyes of thirteen patients (eight normal, sixteen glaucomatous, and two glaucoma suspect eyes) was investigated. After four hours (one to eight hours) an IOP-lowering effect was noted in all eyes, including those otherwise treated with pressure-lowering drugs. The IOP decrease averaged 20%. The time and dosage of the medication, as well as the time of IOP measurement, were optimal in this study; however, the number of patients, the heterogeneity of the patients, and the uncontrolled design limit its value. The IOP-lowering effect suggested by the first pilot study led to a second study: either 10 mg Enalapril b.i.d. or placebo was administered orally and double-blind for 2×6 weeks in a cross-over fashion. IOP was measured seven to nine hours after medication. Only five patients completed the study correctly. Except for a 12% placebo effect, no IOP-lowering effect was noted in this rather unfavorably designed study. In the light of the results obtained in these two studies and the current literature, Enalapril may have an IOP-lowering effect. To determine the value of Enalapril or other ACE inhibitors in the treatment of glaucoma, well-controlled, long-term clinical trials will be necessary. Furthermore, the vasodilative properties of ACE inhibitors and their positive effect in glaucoma treatment remain unstudied. Certainly, local application of ACE inhibitors would be preferable. New ACE inhibitors such as Lisinopril may satisfy this requirement.