Pharmacology and toxicology
Photochemotherapy (PUVA therapy) for extremely severe psoriasis is given either orally or - as preferred today - by external application of 8-methoxypsoralen followed by long-wave UVA irradiation. The psoralen is activated chemically through the UV light, binds more strongly to the DNA, and damages the cells. The cytotoxic effect of PUVA treatment is minimal because of the limited depth of penetration. The European Network of Teratology Information Services (ENTIS) analyzed 41 pregnancies in which systemic PUVA therapy with 8-methoxypsoralen was administered (Garbis 1993). In this study, in which the PUVA therapy was limited to the first trimester, and in a Scandinavian study (Gunnarskog 1993), no indications of embryotoxic effects were reported.
Fumaric acid is used as an antioxidant, in small amounts, in the food industry. With increasing dosages, it is prescribed as therapy in cases of psoriasis (several hundred milligrams daily); leukopenia and lymphopenia may occur as adverse reactions. There is no information about effects on the unborn. However, one of the current authors (C.S.) has documented data on 15 pregnancies treated during the first trimester for psoriasis with numeric acid. No embryotoxic or teratogenic effects were found (there was one spontaneous abortion and one stillbirth).
Recommendation. Photochemotherapy with 8-methoxypsoralen and UVA irradiation is not recommended during pregnancy because of possible mutagenic effects. However, if there has been treatment it does not justify either an interruption of pregnancy or invasive diagnostic procedures. Because of the topical application and the limited area of application, it is unlikely that these agents have substantial risk of developmental toxicity.
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Do You Suffer From the Itching and Scaling of Psoriasis? Or the Chronic Agony of Psoriatic Arthritis? If so you are not ALONE! A whopping three percent of the world’s populations suffer from either condition! An incredible 56 million working hours are lost every year by psoriasis sufferers according to the National Psoriasis Foundation.