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F O Kelsey

Publications and source records attributed to F O Kelsey.

13 recordsLinked to original sources

Teratogen update: vitamin A congeners.

Despite animal vitamin A congener teratogenicity in animal studies since 1954, striking human findings only arose in 1983 following isotretinoin (ITR) marketing for oral treatment of severe acne. By November 1985, 44 outcomes with central nervous system (CNS), cardioaortic (CV), microtia, facial palsy, micrognathia, cleft palate, and/or thymic aplasia defects, and 33 spontaneous abortions have been reported. The critical period for exposure appears to be two to five weeks postconception, although this is clinically inexact. ITR half life is less than a day, although a teratogenic metabolite, 4-oxo-isoretinoin, has a half life of several days. Seven defect outcomes and one stillbirth have been reported with another congener, etretinate (ETR), used for psoriasis. Three of these had meningomyeloceles. Half life of several months makes levels cumulative. Only one additional defect, which may have occurred by chance, is reported with use stopped before conception (4 months). Other discontinuations 1 to 6 months before conception had 11 normal outcomes and two spontaneous abortions. ITR and ETR dose ranged from 0.5 to 1.5 mg/kg. Normal outcomes are reported both with ITR and ETR, but some of these appear not to have been exposed during the critical period. Less striking defects, abortions, and normal outcomes are less well reported. Because vitamin A analogs are therapeutically important and unplanned outcome not always avoidable, further animal research is needed for better risk/benefits. Megadose vitamin A (retinol) use is widespread, but experience poorly observed. Eighteen suspicious birth defect outcomes have been reported from pregnancies with high dose exposure. Twelve had findings similar to those seen in animals and in human retinoid syndromes, e.g., CNS, CV, microtia, and clefts. Epidemiological controls are lacking to establish human teratogenicity, but based on animal studies and experience with ITR and ETR, avoiding long term megadose Vitamin A use in fertile women is warranted.

Abnormalities, Drug-Induced

Regulatory aspects of teratology: role of the Food and Drug Administration.

The Food and Drug Administration is a scientific regulatory agency whose consumer protection activities cover a wide range of products including foods and additives, and pesticide residues on foods; drugs; cosmetics; medical devices; and radiation-emitting electronic products. Amongst its concerns is the possible teratogen effects of regulated products to which the pregnant woman is exposed. The policies and programs of the agency directed toward reducing such risks to the unborn are reviewed. These measures include guidelines for animal reproduction studies and for clinical trials involving women to childbearing potential; labeling of products to disclose known or possible harm to the fetus or embryo; surveillance procedures designed to detect previously unsuspected adverse effects of marketed products; research activities designed to develop better understanding of developmental toxicology and improved techniques for detecting embryocidal and embryotoxic effects; and educational efforts directed both to professionals and the public regarding hazards to the unborn of agency-regulated products.

Abnormalities, Drug-Induced

Drugs and pregnancy.

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Abnormalities, Drug-Induced