Topical mecamylamine for diabetic macular edema.
Peter A Campochiaro1, Syed Mahmood Shah, Gulnar Hafiz
1Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA. pcampo@jhmi.edu
American Journal of Ophthalmology
|March 2, 2010
Summary
Topical mecamylamine showed heterogeneous effects in diabetic macular edema patients. While generally safe, its impact on vision and retinal thickness varied significantly, suggesting a need for further research into receptor subtypes.
Area of Science:
- Ophthalmology
- Pharmacology
- Vascular Biology
Background:
- Nicotinic acetylcholine (nACh) receptors on vascular endothelial cells influence angiogenesis and permeability.
- Diabetic macular edema (DME) is a significant cause of vision loss in diabetic patients.
- Mecamylamine is a non-specific nACh receptor antagonist.
Purpose of the Study:
- To evaluate the safety and bioactivity of topical mecamylamine in patients with diabetic macular edema.
- To assess the effects of mecamylamine on visual acuity and foveal thickness in DME patients.
Main Methods:
- A multicenter phase I/II clinical trial involving 23 patients with chronic diabetic macular edema.
- Patients received 1% mecamylamine drops twice daily for 12 weeks.
- Safety assessments, best-corrected visual acuity (BCVA), and optical coherence tomography (OCT) for foveal thickness were performed.
Main Results:
- Topical mecamylamine was well-tolerated with no drug-related safety issues.
- Mean BCVA showed variable improvement over the 16-week study period.
- Significant heterogeneity in patient response was observed, with some showing improvement and others no change or worsening.
- Five patients demonstrated improvement after discontinuing mecamylamine.
Conclusions:
- Topical mecamylamine exhibited heterogeneous effects in patients with diabetic macular edema.
- Variable expression of nACh receptor subtypes may explain the diverse patient responses.
- Further investigation into specific nACh receptor blockers is warranted to dissociate anti-permeability and pro-permeability effects.
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