Use of Calcium Channel Blockers for Glaucoma

Use of Calcium Channel Blockers for Glaucoma

What are Calcium Channel Blockers and Why Might they be of Benefit in the Treatment of Glaucoma?

Mounting evidence suggests that factors other than intraocular pressure (IOP) contribute to the development of glaucoma.[1]  One suspected factor is blood flow to the eye.[2] Calcium channel blockers dilate blood vessels potentially leading to increased blood flow. This class of medication has been used successfully to treat abnormal blood flow conditions such as migraine headache[3] and Raynaud’s[4] (both of which may be associated with glaucoma). Additionally, calcium channel blockers may have a neuroprotective effect.[5] Examples of Calcium channel blockers include verapamil (Calan, Covera-HS, Verelan), nifedipine (Procardia), and diltiazem (Cardizem, Dilacor, Tiazac).

Evidence that Calcium Channel Blockers can be effective in the treatment of Glaucoma

For over two decades calcium channel blockers have been studied as a potential treatment of glaucoma.[6] There is evidence that nifedipine (a commonly used calcium channel blocker) can stabilize visual fields in those with normal tension glaucoma and/or those with peripheral vascular disease.[7] This potential benefit may be due to an increase in blood supply to the eye.[8]

However, in 2001 results were published of a placebo controlled trial investigating the effect of nifedipine on both optic nerve blood flow and visual fields in patients with open angle glaucoma.[9] No significant effect was noted in either optic nerve blood flow or visual fields in those study participants using nifedipine compared to those using placebo.

It is possible that no benefit of nifedipine was noted as the study had to be prematurely terminated. Why? Because a full third of the study participants taking nifedipine dropped out of the study due to headache, flushing, dizziness, swelling and/or low blood pressure. Sixty percent of those remaining in the nifedipine study arm experienced side-effects including headache, dizziness and nausea.

Other studies have documented similar side effects with the use of calcium channel blockers. More worrisome is the evidence that short-acting nifedipine can increase the risk of death in those who have coronary artery (heart) disease.[10] Long-term use of calcium channel blockers may even increase the risk of certain cancers such as breast cancer.[11]

Summary

Although in theory calcium channel blockers have the potential to benefit those with glaucoma, this benefit has not been demonstrated in humans. Additionally, this class of medications is associated with significant systemic side effects.[12] Even in low doses these risks would likely outweigh the unproven potential benefit of calcium channel blockers to those with glaucoma.

References

1) Sommer A, Tielsch JM, Katz J, et al. Relationship between intraocular pressure and primary open angle glaucoma among white and black Americans. The Baltimore Eye Survey. Arch Ophthalmol 1991;109:1090-1095.

2) Flammer J, Orgül S. Optic nerve blood-flow abnormalities in glaucoma. Prog Retin Eye Res 1998;17: 267-289.

3) Gelmers HJ. Calcium-channel blockers in the treatment of migraine. Am J Cardiol 1985;55:139B.

4) Rodeheffer RJ, et al. Controlled double-blind trial of nifedipine in the treatment of Raynaud’s phenomenon. N Engl J Med 1983;308:880.

5) Fitzgerald  M,  Payne  SC,  Bartlett  CA,  Evill  L,  Harvey  AR, Dunlop  SA.  Secondary retinal ganglion cell death and the neuroprotective effects of the calcium channel  blocker lomerizine. Invest Ophthalmol Vis Sci 2009;50: 5456-5462.

6) Netland PA, Chatuverdi N, Dreyer EB. Calcium channel-blockers in the management of low-tenstion and open-angle glaucoma. Am J Ophthalmol 1993;115:608-613.

7) Gaspar AZ, Flammer J, Hendrickson Ph. Influence of nifedipine on the visual fields of patients with optic-nerve-head diseases. Eur J Ophthalmol 1994;4:24-28.

Gasser P, Flammer J. Short- and long-term effect of nifedipine on the visual field in patients with presumed vasospasm. J Int Med Res 1990;18:334-339.

8) Miyoshi T. Effect of nifedipine on choroidal circulation. 1. Change of choroidal blood flow in rabbits. Trans Jpn Soc Ophthalmol 1984;35:664-670.

9) Rainer G, Kiss B, Dallinger S, et al. A double masked placebo controlled study on the effect of nifedipine on optic nerve blood flow and visual field function in patients with open angle glaucoma. Br J Clin Pharmacol. 2001;52(2): 210–212.

10) Furberg CD, Psaty BM, Meyer JV. Nifedipine. Dose-related increase in mortality in patients with coronary heart disease. Circulation 1995; 92:1326.

11) Li CI, Daling JR, Tang MT, et al. Use of antihypertensive medications and breast cancer risk among women aged 55 to 74 years. JAMA Intern Med 2013; 173:1629.

12) Conlin PR, Williams GH. Use of calcium channel blockers in hypertension. Adv Intern Med 1998;43:533-562.

Don’t delay getting checked for glaucoma.

Make an appointment with an eye doctor in your area now.  If you live in the greater Los Angeles area and would like Dr. Richardson to evaluate your eyes for glaucoma call 626-289-7856 now. No referral required. Same day or next day appointments are available, Tuesday through Saturday.

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