The most common adverse events ( occurring in > 3 % of patients ) were increased - glutamyltransferase ( 14 [ 10 % ] patients in the idalopirdine group vs two [ 2 % ] in the placebo group ) , diarrhoea ( six [ 4 % ] vs nine [ 7 % ] ) , urinary tract infection ( three [ 2 % ] vs nine [ 7 % ] ) , fall ( three [ 2 % ] vs eight [ 6 % ] ) , increased alanine aminotransferase ( nine [ 6 % ] vs none ) , and benign prostatic hyperplasia ( two [ 5 % ] vs none ) .