Adverse drug reactions of the skin in geriatric patients when taking medications with a risk of photosensitization

Background. Multiple comorbid conditions in the geriatric population are associated with changes in the classical clinical picture of diseases and the nature of their course, an increase in the number and severity of complications, a deterioration in quality of life (QL), and a decrease in functional activity. The desire to increase the effectiveness of treatment, to help the patient recover from all the diseases he has, inevitably leads to the appointment of a large number of drugs. The negative consequences of polypragmasia include: an increase in the incidence of adverse drug reactions (ADR), the development of geriatric syndromes, a decrease in the effectiveness of treatment and complianceto it, a decrease in the patient's QL, an increase in the frequency of hospitalizations and mortality due to a decrease in the effectiveness and safety of therapy, and an increase in the cost of treatment. Elderly and senile patients are particularly vulnerable to ADR. Undesirable reactions may occur atypically in them. A strikingexample is the adverse light-dependent skin reactions when taking drugs with the risk of photosensitization. Photosensitizing substances are drugs that, with resorptive or local action, increase skin sensitivity to sunlight or artificial ultraviolet rays (UVR). Compounds that make the skin hypersensitive to UVR are found in many medications. Once in the body, thesedrugs are converted into various metabolites and accumulate in tissues, and when activated byUVR, cause phototoxic or photoallergic reactions. In response to the effects of a combination of such drugs and UVR, edema, nodules, spots, vesicles, acute eczematous reaction, and urticaria appear. Epithelial desquamation, hyper- and hypopigmentation of the skin are also possible. Hypersensitivity to UVR can persist for several months after the withdrawal of photosensitizing drugs.