Document Detail

A double-blind study of cysteine photoprotection in erythropoietic protoporphyria.
MedLine Citation:
PMID:  7727280     Owner:  NLM     Status:  MEDLINE    
In an open trial in 9 patients, we found that the ingestion of 500 mg of cysteine twice a day could prevent or lessen the photosensitivity associated with erythropoietic protoporphyria (EPP). We report here the results of a double-blind cross-over design trial in 16 patients. Patients with EPP were randomized into two groups, one that received 500 mg twice daily of cysteine during the first period and then placebo during the second period, and the second that received placebo first and then cysteine. Each drug ingestion period lasted 8 weeks, and there was a 1 week wash-out period between them. Patients were seen before the first period, at the end of the first period and at the end of the second period for phototesting, an objective method of assessing treatment efficacy, and for blood tests to monitor cysteine safety. The subjects also were asked to keep light-exposure diaries, a subjective method of assessing efficacy. We found that cysteine significantly prolonged the time it took to develop erythema by phototest, objectively demonstrating efficacy. In addition, analysis of patients' diaries showed that cysteine ingestion significantly increased the length of sun exposure it took to develop symptoms of photosensitivity. We conclude that cysteine ingestion may be an effective therapy in the prevention of photosensitivity associated with EPP.
M M Mathews-Roth; B Rosner; K Benfell; J E Roberts
Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Photodermatology, photoimmunology & photomedicine     Volume:  10     ISSN:  0905-4383     ISO Abbreviation:  Photodermatol Photoimmunol Photomed     Publication Date:  1994 Dec 
Date Detail:
Created Date:  1995-06-01     Completed Date:  1995-06-01     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  9013641     Medline TA:  Photodermatol Photoimmunol Photomed     Country:  DENMARK    
Other Details:
Languages:  eng     Pagination:  244-8     Citation Subset:  IM    
Channing Laboratory, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.
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MeSH Terms
Cross-Over Studies
Cysteine / administration & dosage,  blood,  therapeutic use*
Double-Blind Method
Erythema / prevention & control
Medical Records
Middle Aged
Photosensitivity Disorders / prevention & control*
Porphyria, Hepatoerythropoietic / prevention & control*
Grant Support
Reg. No./Substance:
0/Placebos; 52-90-4/Cysteine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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