Gastroduodenal bleeding, a serious NSAID-related adverse event, has been found highly probable in CYP2C9*1/*3 and CYP2C9*1/*2 heterozygotes [101] A later study recognized the CYP2C9 359Leu (CYP2C9*3) allele as a risk factor for acute upper gastrointestinal bleeding in patients taking NSAIDs other than aspirin. This evidence concerns the gene CYP2C9 and Abnormal bleeding.