All patients received amitriptyline at a dose of 12.5 mg in the first week and 25 mg over the subsequent 4 weeks. Patients of group 1 (n = 15) received 125 mL 0.9% saline and patients of group 2 (n = 15) received 240 mg lidocaine diluted in 125 mL 0.9% saline. The solutions were infused over a period of 1 h, once a week, for 4 weeks (T1, T2, T3 and T4).