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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Administration, Cutaneous, Adult, Calcitriol, Cholecalciferol, Combined Modality Therapy, Dermatologic Agents, Female, Humans, Male, Middle Aged, Prospective Studies, Psoriasis, Severity of Illness Index, Treatment Outcome, Ultraviolet Therapy.
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Is clinical effect of vitamin D3 analogues inactivated by subsequent UV exposure? Context: Combining phototherapy with topical vitamin D3 analogues is a useful therapy for the treatment of psoriasis by reducing the cumulative UV dose required for clearance of lesions. Experimental investigations demonstrated that calcipotriol is degraded by UV radiation, and suggested that calcipotriol should be applied after phototherapy but not immediately before. Calcipotriol or maxacalcitol ointment was topically applied to psoriatic plaques of six patients immediately before or after phototherapy on the right or left side of the body, respectively. Topical application of vitamin D3 analogues either before or after irradiation by psoralen and UVA radiation (PUVA) or narrow-band (NB)-UVB showed exactly similar effects in all patients.
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Therapeutic effects of vitamin D3 analogues are not clinically inactivated by subsequent irradiation with PUVA or NB-UVB phototherapy. Final Decision: no