For several decades the discovery of the effectiveness for the treatment of pain with drugs whose creation had other aims, opened the door to new opportunities to diminish the suffering of patients and to improve its quality of life.The first drugs that were used were tricyclic antidepressants and later this use was extended to anticonvulsivants, anesthetics,bisphosphonates, antidepressives, serotonin and norepinephrine reuptake inhibitors, among others.In spite of this, effectiveness for pain control is very variable, according to the type of pathology and in some cases of associated diseases. Therefore is necessary to do an analysis of each patient to define the suitable drug and the necessity of several active principles that complement to each other. It`s important not to forget that the approach to a patient with pain, specially a chronic one, must be interdisciplinary involving the areas of mental health and the rehabilitation, looking for toavoid complications, majors incapacities and to obtain the best social and work adaptation of patients.