Consistency of listed indications and contraindications between the U.S., the U.K., Japan, and Korea on prescription drug labels

Abstract

Inclusion of indications and contraindications in drug labeling is essential for drug approval. Little is known regarding how well new drug information labels agree across countries. To compare the number of indications and contraindications on the labels of drugs in the U.S., U.K., Japan, and Korea, we selected 81 new drugs approved in these countries between 2008 and 2016 and assessed the number of indications and contraindications on each label. Average and median numbers with standard deviations were presented for the 81-drug set, and for subsets grouped according to drug class. Correlation analyses were conducted to estimate Pearson and concordance correlation coefficients. No significant difference was observed across countries in the number of indications, the average being 1.69, 1.67, 1.54, and 1.51 in the U.S., the U.K., Korea, and Japan (p = 0.31), respectively. By contrast, substantial variation was observed in the number of contraindications, the average being 1.54, 2.42, 3.53, and 3.00 in the U.S., the U.K., Korea, and Japan (p < 0.001), respectively. Pearson correlation coefficients comparing contraindications were 0.40, 0.48, and 0.47 for U.S.-U.K., U.S.-Korea, and U.S.-Japan, but 0.83, 0.73, and 0.71 for U.K.-Korea, U.K.-Japan, and Korea-Japan, respectively (p < 0.01). There is consistency in the number of indications, but a substantial discrepancy in contraindications listed in drug labeling across countries. Further study is warranted to improve global harmonization of contraindication listings.