
    the study was early terminated due to insufficient recruitment
  
['chronic pain']
['gabapentin', 'tramadol']

        Inclusion Criteria:

          1. Male or female, aged 3 months to less than 18 years at screening.

          2. Informed consent by parent(s) and/or legal guardian according to each country legal
             requirement.

          3. Assent by the patient, where applicable, according to each country legal requirement.

          4. Subjects that meet the diagnostic criteria for neuropathic or mixed pain.

          5. Subjects that present with chronic pain defined as the recurrent or continuous pain
             persisting more than 3 months. Duration of pain will be determined from the date of
             the first pain experienced.

          6. Subjects that present with at least moderate pain as defined by average pain intensity
             of ≥4/10 as assessed during a 3-day screening period

          7. Stable underlying disease condition and treatment.

          8. In presence of malignant diseases, subjects in clinical remission and/or no expected
             changes in their therapeutic protocol during participation to the present study.

        Exclusion Criteria:

          1. Pain duration of more than 5 years.

          2. Current use of gabapentin or tramadol.

          3. History of failure to respond to adequate treatment by gabapentin or tramadol/opioids
             for neuropathic pain.

          4. History of epileptic condition except febrile seizure disorder.

          5. Subjects with sleeping apnoea syndrome of any origin or subjects with history of
             severe respiratory impairment.

          6. Subjects with diagnosis of sickle cell disease.

          7. Subjects that present significant cognitive impairment.

          8. Subjects that present current, controlled or uncontrolled, co-morbid psychiatric
             diagnosis that can impair pain diagnosis and assessment such as severe depressive
             conditions or psychosis.

          9. Subjects with history of suicidal ideation or behaviour.

         10. History of substance abuse in particular opioids.

         11. Subjects under prohibited concomitant medication

         12. Subjects in need for corticosteroid oral treatment or corticosteroid infiltrations to
             treat pain caused by infiltration or compression of neural structures, e.g. peripheral
             nerves or spinal cord.

         13. Subjects born prematurely at ≤ 36 weeks gestational age, if recruited during the first
             year of age.

         14. Subjects with a body mass index (BMI) for age and gender of < 5th percentile or > 95th
             percentile.

         15. Subjects with glomerular filtration rate < 90 mL/min/1.73 m2 (Schwarz equation).

         16. Subjects with significant hepatic impairment or with Aspartate Transaminase (AST) or
             Alanine Transaminase (ALT) enzymes 3 times the upper limit of the age-specific
             reference range.

         17. Subjects with known allergy, hypersensitivity or clinically significant intolerance to
             gabapentin or tramadol or any component found in the study drugs.

         18. Subjects with fructose intolerance, diabetes, glucose-galactose malabsorption or
             lactase-isomaltase deficiency.

         19. Subjects with clinically relevant abnormal ECG at the screening visit in the
             discretion of the Investigator/cardiologist.

         20. Subjects participating in another clinical interventional trial.

         21. Subjects scheduled for surgery or in recovery from surgery occurring within 3 months
             of baseline assessment.

         22. Female subjects who are pregnant or currently lactating.

         23. Subjects that failed screening or were previously enrolled in this study.
      