Abstract
A variety of medicinal products have been associated with rash and normally this information should be available in the Summary of Product Characteristics (SmPCs). Our study aimed to investigate the frequency of rash as an adverse drug reaction, based on the information provided by SmPCs of 1,048 single active substances (international non-proprietary names) authorized in the United Kingdom. Data on rash frequency was collected from each SmPC using automated searches based on selected keywords. Data analysis was carried out using R, v. 3.4. We found that over 90% of the medicines used orally or by injection may be associated with rash as an adverse event, the most common classes being protein kinase inhibitors, anticancer medicinal products, monoclonal antibodies, biologicals, antivirals and retinoids, with high variations in rash frequency for products within the same class, but also for products with the same active substance. Analysis of SmPCs revealed the need to increase homogeneity in reporting rash frequency, by using Council for International Organizations of Medical Sciences classification, and Medical Dictionary for Regulatory Activities coding in a more standardized manner, and also the need to include more safety endpoints in clinical trials and to use better the safety results for publication and updating the SmPCs.