After 14 days , patients in the minocycline and amitriptyline groups reported a reduction of 1.47 ( 95 % confidence interval , 0.16-2 .83 ; P = 0.035 ) and 1.41 ( 95 % confidence interval , 0.05-2 .78 ; P = 0.043 ) , respectively , in the numeric rating scale compared to the placebo group .