Retinitis Pigmentosa Medication

Updated: Apr 06, 2017
  • Author: David G Telander, MD, PhD; Chief Editor: Donny W Suh, MD, FAAP  more...
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Medication

Medication Summary

The goals of pharmacotherapy are to reduce morbidity and to prevent complications. In addition to the medications listed below, the use of lutein to human disease(s) is uncertain, although lutein apparently may slow retinal degeneration, according to Glickman et al. Doses of 20 mg/d have been recommended.

Although bilberry is recommended by some practitioners of alternative medicine in doses of 80 mg/day, no controlled studies exist documenting its safety or efficacy in treating RP.

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Vitamins, Fat-Soluble

Class Summary

May delay RPE degeneration.

Vitamin A (Aquasol A, A-Natural, A-25)

Use of antioxidants in treating RP might be beneficial, but no evidence exists in favor of vitamin supplementation and possibly some slight evidence to the contrary. A comprehensive epidemiologic study by Norton et al concluded that very high daily doses of vitamin A palmitate (15,000 U/d) slow the progress of RP by about 2% per year. The effects are also modest, and the use of such treatment must be weighed against the uncertain risk of long-term adverse effects from large chronic doses of vitamin A. Yearly checks of liver enzymes and vitamin A levels are recommended.

While vitamin A is found almost exclusively in animals (eg, fish oil, liver), beta-carotene is found predominantly in leafy green vegetables. Beta-carotene has about one-sixth the bioavailability of vitamin A and is cleaved by the intestinal mucosa using the enzyme dioxygenase. It is reduced with 2 NADPH into retinol or vitamin A. Because of the body's limited ability to generate vitamin A from beta-carotene, it is nontoxic, even in amounts 6 times more than the US RDA.

Vitamin E (Aquasol E, Alph-E, Aqua Gem-E)

High doses of vitamin E (400 U/d) were modestly deleterious, according to Berson et al, nevertheless, doses as high as 800 IU/d have been recommended.

Ascorbic acid (Acerola, C-Gel, Ascocid, Vita-C)

Although doses of 1000 mg/d are recommended anecdotally, according to Naka et al, no evidence exists that ascorbic acid is helpful in RP.

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Calcium channel blockers

Class Summary

Reduce toxic levels of cyclic GMP in the RPE.

Diltiazem (Cardizem, Diltzac, Tiazac)

Experimental therapy. A recent study by Frasson showed decreased degeneration of the retina in rd mutant mice. Homologous mutations in humans represent about 4% of patients with RP. No current recommendations exist regarding the use of diltiazem, a calcium channel blocker commonly used in cardiac disease, in any patients with RP, including those with the homologous mutation.

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Carbonic anhydrase inhibitors

Class Summary

Reduce cystoid macular edema associated visual loss from RP.

Acetazolamide (Diamox Sequels)

In a small percentage of patients with RP, cystoid edema may respond to oral carbonic anhydrase inhibitors, such as acetazolamide, with some subjective improvement in visual function, according to Fishman et al. These may be patients in whom the macular RPE is relatively uninvolved by disease, since carbonic anhydrase inhibitors must act upon functional RPE to enhance water transport, according to Marmor. Topical CAIs have not been evaluated.

Methazolamide (Neptazane)

Reduces aqueous humor formation by inhibiting enzyme carbonic anhydrase, which results in decreased IOP.

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