[Geriatric dermatopharmacology].

Skin aging is associated with alterations regarding its barrier function, the amount and composition of lipids, as well as the cutaneous blood flow. All these factors affect the absorptive capacity of the skin. As a major clinical problem after topical application in aged patients, we find increased toxicity of salicylates (strong absorption, permeation and resorption, elevated free serum fraction, increased renal toxicity) and coffein (decreased hepatic clearance). Sun-ray filter creams protecting against UVB only will decrease the synthesis of vitamin D, and a prolonged exposure to the sun will results in an increased metabolism by UVA of vitamin D leaving inactivated compounds. This again is of special importance since, in the elderly, we usually find the synthesis of vitamin D already decreased. Therefore, these patients should be treated with sun-ray filter creams providing protection against both UVA and UVB.