TY - JOUR

T1 - Cimetidine for erythropoietic protoporphyria

AU - Heerfordt, Ida M.

AU - Lerche, Catharina M.

AU - Wulf, Hans Christian

N1 - Funding Information: We thank the patients for granting permission to publish their case details. We thank Louise Holbæk Kaihøi, Copenhagen University Hospital, for secretarial assistance. This work was supported by a grant from the Alfred Benzon Foundation, Denmark. The funder had no role in study design, data collection, analysis, decision to publish, or preparation of the manuscript. Funding Information: We thank the patients for granting permission to publish their case details. We thank Louise Holb?k Kaih?i, Copenhagen University Hospital, for secretarial assistance. This work was supported by a grant from the Alfred Benzon Foundation, Denmark. The funder had no role in study design, data collection, analysis, decision to publish, or preparation of the manuscript. Publisher Copyright: © 2022

PY - 2022

Y1 - 2022

N2 - Background: Erythropoietic protoporphyria (EPP) is caused by deficiency of the enzyme converting protoporphyrin IX (PpIX) into heme resulting in accumulation of PpIX; leading to photosensitivity and liver toxicity. Cimetidine might inhibit δ-aminolevulinic acid synthase influencing the heme biosynthesis. We present cases with EPP treated with cimetidine at our department, and a literature review. Methods: Systematic searches were performed to identify literature describing EPP patients treated with cimetidine. On that ground we treated EPP patients with cimetidine through spring and summer in 2020 and 2021 at our department. Their erythrocyte PpIX level and standard blood and liver parameters were collected before and during 4 months of treatment. Using a questionnaire, patients were asked about change in photosensitivity, side effects, and whether they would like to resume treatment in the spring of 2022. Results: Literature searches identified 9 patients treated with cimetidine. Four were outpatients reporting decreased photosensitivity. At our department 18 outpatients started treatment. Fifteen used oral cimetidine daily for 4 months or more providing a significant decrease in erythrocyte PpIX with a median of 20% (range: -18% to 53%) after 4 months. Eleven of the 15 patients reported a decrease in photosensitivity during treatment, 3 patients were unsure, and 1 patient experienced unchanged photosensitivity. Only mild side effects were reported. Fourteen patients requested to resume treatment in the spring of 2022. Conclusions: These cases suggest that cimetidine can lower erythrocyte PpIX in patients with EPP.

AB - Background: Erythropoietic protoporphyria (EPP) is caused by deficiency of the enzyme converting protoporphyrin IX (PpIX) into heme resulting in accumulation of PpIX; leading to photosensitivity and liver toxicity. Cimetidine might inhibit δ-aminolevulinic acid synthase influencing the heme biosynthesis. We present cases with EPP treated with cimetidine at our department, and a literature review. Methods: Systematic searches were performed to identify literature describing EPP patients treated with cimetidine. On that ground we treated EPP patients with cimetidine through spring and summer in 2020 and 2021 at our department. Their erythrocyte PpIX level and standard blood and liver parameters were collected before and during 4 months of treatment. Using a questionnaire, patients were asked about change in photosensitivity, side effects, and whether they would like to resume treatment in the spring of 2022. Results: Literature searches identified 9 patients treated with cimetidine. Four were outpatients reporting decreased photosensitivity. At our department 18 outpatients started treatment. Fifteen used oral cimetidine daily for 4 months or more providing a significant decrease in erythrocyte PpIX with a median of 20% (range: -18% to 53%) after 4 months. Eleven of the 15 patients reported a decrease in photosensitivity during treatment, 3 patients were unsure, and 1 patient experienced unchanged photosensitivity. Only mild side effects were reported. Fourteen patients requested to resume treatment in the spring of 2022. Conclusions: These cases suggest that cimetidine can lower erythrocyte PpIX in patients with EPP.

KW - Cimetidine

KW - Erythropoietic protoporphyria

KW - Hepatology

KW - Photosensitivity

KW - Protoporphyrin IX

KW - Questionnaire

U2 - 10.1016/j.pdpdt.2022.102793

DO - 10.1016/j.pdpdt.2022.102793

M3 - Journal article

C2 - 35245673

AN - SCOPUS:85127009818

VL - 38

JO - Photodiagnosis and Photodynamic Therapy

JF - Photodiagnosis and Photodynamic Therapy

SN - 1572-1000

M1 - 102793

ER -