Treatment was stopped more often in the nortriptyline group ( 19 [ 29 % { 95 % CI , 19 % -42 % } ] ) than in the placebo group ( 6 [ 9 % ] { 95 % CI , 3 % -19 % } ] ) ( P = .007 ) , but numbers of adverse events were not different ( 27 [ 95 % CI , 18-39 ] vs 28 [ 95 % CI , 19-40 ] ) ( P = .89 ) .