The existence of somatosensory nervous system damage and the consequent occurrence of
neuropathic pain is an important factor in the development of many painful syndromes, both
benign and cancerous pain. A particular feature of this syndrome is that patients with the
same pathology (eg painful diabetic neuropathy) exhibit a different spectrum of symptoms and
clinical signs whereas patients with different pathologies (such as diabetic neuropathy and
postherpetic neuralgia) often have the same clinical picture. This phenomenon has been
attributed to the different pathophysiological mechanisms involved in each case, regardless
of the initial causative agent that induced the nerve damage. Among these mechanisms the
occurrence of ectopic electrical activity in the periphery, the development of central
sensitization, spinal cord remodeling as well as the phenotypic differentiation of neurons
are included. In the treatment of neuropathic pain, a large number of agents have been used,
such as antiepileptics, antidepressants, topical anesthetics, opioids, capsaicin etc. Among
these, the highest efficacy, based on existing evidence, is proved with gabapentinoids
(Gabapentin and Pregabalin) and antidepressants (serotonin and noradrenaline reuptake
inhibitors) as well as Tramadol. The distinction of different phenotypes of neuropathic pain
is done either by using specific questionnaires or by laboratory assessment. Regarding the
use of questionnaires, the PAIN DETECT questionnaire has been used to distinguish 5 different
phenotypes of neuropathic pain in patients with diabetic neuropathy, postherpetic neuralgia
and back pain, and is considered as an acceptable method despite its limitations in the
detection of different phenotypes of neuropathic painStudy protocol
Patients meeting the inclusion criteria are informed for and included in the study after
written consent. Patients should note that this is an observational study and that the
treatment they will receive is appropriate for their case, as documented in international
guidelines. None will not receive an experimental or other medicine other than the medically
accepted ones in their case and their treatment will be the same whether they are
participating in the study or not. An initial assessment will be made to patients. During the
initial assessment, demographic data, pain intensity with Numerical rating scale (NRS) and
Short Form McGill Pain questionnaire, as well as location, reflections and periodicity are
recorded. Additionally, patients are assessed on the basis of SOPA SF and PAIN
Catastrophising scale questionnaires. Patients are then assessed for neuropathic pain with
the DN4 and PAIN DETECT questionnaires. Since the latter are diagnostic of neuropathic pain,
patients are divided into 2 groups. Group A begins to administer Pregabalin 50 mg daily with
a gradual increase of 50 mg every 5 days to a dose of 300 mg daily or the highest tolerated
dose based on adverse reactions. In group B, Duloxetin is administered at a dose of 30 mg,
increasing to 60 mg daily after 15 days, in the absence of adverse events. Patients are
re-evaluated after a 30-day NRS, McGill Pain questionnaire and PAIN DETECT scale for the
range of sensory symptoms and signs. Since the reduction in pain intensity is less than 50%
in the NRS, the second therapeutic agent is added as follows: Group A addition of Duloxetine
at a dose of 30 mg, increasing to 60 mg daily after 15 days, in the absence of adverse
effects. Group: Add Pregabalin 50mg with a gradual increase of 50mg per 5 days to a daily
dose of 300mg or up to the maximum tolerated dose. Patients are re-evaluated 30 days after
the addition of the second agent based on the NRS scale, McGill Pain Questionnaire and PAIN
DETECT on the range of sensory symptoms and signs. Since the reduction in pain intensity is
less than 50% in the NRS, the combination of the two agents in the two groups is added
Tramadol 50 mg twice a day. Patients are re-evaluated after the latency of one month after
the addition of Tramadol, and the final values in the NRS, PAIN DETECT SF McGill ranges are
obtained. If at any stage of the treatment one of the drugs is not tolerated, it is
discontinued, the patients are withdrawn from the study and by further measurements the case
is recorded and the patient's alternative treatment methods are discussed with the patient.
Ethics
The study is a prospective cohort-type observational study and will include the recording of
patients' clinical parameters without affecting their health, influencing the diagnostic or
therapeutic approach, affecting the outcome of their health or violating their legal rights.
Patient data will be recorded anonymously, and any publication of the results will take place
in the form of aggregated tables, which does not contradict the personal or religious beliefs
of patients.