Calcium channel blockers may increase the risk of glaucoma

Up to 40% of patients with hypertension in the United Kingdom are prescribed a calcium channel blocker (CCB), with CCBs accounting for almost 4% of all primary care prescriptions. An exploratory study of US insurance claims data and several population-based studies have suggested that CCB use is associated with incident glaucoma, but these studies had several limitations. To further investigate this issue, a new UK study has examined the association between systemic CCB use and the risk of glaucoma and related traits. The population-based cross-sectional study included UK Biobank participants who had complete data for analysis of glaucoma status, intraocular pressure (IOP), and optical coherence tomography (OCT)–derived inner retinal layer thicknesses. The primary outcome measures in the study were glaucoma status, corneal-compensated IOP, and two OCT-derived inner retinal thickness parameters (macular retinal nerve fibre layer [mRNFL] and macular ganglion cell–inner plexiform layer [mGCIPL] thicknesses), which served as objective structural glaucoma-related biomarkers. Results showed the following: Of 427,480 adults in the study, the median age was 58 years, 54.1% were women and 7.8% (n=33,175) were CCB users. Dihydropyridines (e.g., amlodipine) were the most commonly used CCB subtype (88.4%), followed by benzothiazepines (e.g., diltiazem; 9.1%) and phenylalkylamines,(e.g., verapamil; 2.9%). Analyses included participants who had complete data for glaucoma status (n=427,480), IOP (n=97,100) and OCT-derived inner retinal layer thicknesses (n=41,023). After adjustment for key sociodemographic, medical, anthropometric and lifestyle factors, use of CCBs was associated with greater odds of glaucoma (odds ratio [OR], 1.39 [95%CI, 1.14–1.69]; p=0.001). Other antihypertensive agents, including diuretics, renin-angiotensin system inhibitors and systemic β-blockers, were not associated with greater odds of glaucoma. CCB use was also associated with thinner mGCIPL (−0.34 μm [95%CI, −0.54 to −0.15 μm]; p=0.001) and mRNFL (−0.16 μm [95%CI, −0.30 to −0.02 μm]; p=0.03) thicknesses, but not IOP (−0.01 mmHg [95%CI, −0.09 to 0.07mmHg]; p=0.84). The investigators conclude that in this study, CCB users had, on average, a 39% higher odds of glaucoma compared to nonusers. CCB use was also associated with thinner mGCIPL and mRNFL thicknesses, providing a structural basis that supports the association with glaucoma. The authors observed no difference in mean IOP between CCB users and nonusers. They contend that the lack of association of CCB use with IOP suggests that an IOP-independent mechanism of glaucomatous neurodegeneration may be involved. The authors maintain that further research is required to determine whether the association between CCB use and glaucoma is causal and to investigate potential underlying biological mechanisms. They also suggest that although a causal relationship between CCB use and development of glaucoma has not yet been established, CCB withdrawal or replacement could be considered if glaucoma progresses despite optimal care. Reference 1. Kastner A, Stuart KV, Montesano G, et al; UK Biobank Eye and Vision Consortium. Calcium channel blocker use and associated glaucoma and related traits among UK Biobank participants. JAMA Ophthalmol 2023. Published online September 7, 2023. (accessed September 7, 2023).

Calcium channel blockers may increase the risk of glaucoma

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