Serrano G, Fortea J M, Latasa J M, SanMartin O, Bonillo J, Miranda M A
Department of Dermatology, University General Hospital, Valencia, Spain.
J Am Acad Dermatol. 1992 Apr;26(4):545-8. doi: 10.1016/0190-9622(92)70077-s.
The mechanism of piroxicam-induced photosensitivity is unknown. It was first attributed to metabolites of the drug produced in vivo but further photochemical studies disclosed that piroxicam was not stable to light, forming at least two photoproducts. Photosensitivity reactions to droxicam and tenoxicam have been not reported.
The aim of this study was to determine whether piroxicam photoproducts contribute to the light reactions induced by this drug, to describe a case of droxicam-induced photosensitivity and to study the in vivo photosensitizing potential of tenoxicam.
Patch and photopatch tests with two major photoproducts of piroxicam, with different preparations of UVA-preirradiated piroxicam, and with low and high concentrations of tenoxicam were performed in normal volunteers and in piroxicam-photosensitive patients. Phototesting studies were also performed before and after the oral administration of tenoxicam in both groups of subjects.
Positive patch test responses were obtained in piroxicam-photosensitive patients only with the preirradiated piroxicam preparations. Phototesting studies with tenoxicam were normal in both groups.
Minor or intermediate piroxicam photoproducts are more likely to be responsible for the photosensitivity reactions induced by this drug.
吡罗昔康引起光敏反应的机制尚不清楚。它最初被认为是由体内产生的药物代谢产物引起的，但进一步的光化学研究表明，吡罗昔康对光不稳定，至少会形成两种光产物。尚未有关于屈昔康和替诺昔康引起光敏反应的报道。
本研究旨在确定吡罗昔康光产物是否会导致该药物引起的光反应，描述1例屈昔康引起的光敏反应病例，并研究替诺昔康的体内光敏潜力。
在正常志愿者和吡罗昔康光敏患者中，用吡罗昔康的两种主要光产物、不同的紫外线预照射吡罗昔康制剂以及低浓度和高浓度的替诺昔康进行斑贴试验和光斑贴试验。两组受试者口服替诺昔康前后也进行了光试验研究。
仅在紫外线预照射吡罗昔康制剂的情况下，吡罗昔康光敏患者的斑贴试验呈阳性反应。两组患者用替诺昔康进行的光试验研究结果均正常。
吡罗昔康的次要或中间光产物更有可能是该药物引起光敏反应的原因。
