Randomized, double-blind, double-dummy, active controlled, multicentre, non-inferiority phase-III study to compare the pharmacokinetics, efficacy and safety of gabapentin liquid formulation to tramadol in children from 3 months to less than 18 years of age experiencing moderate to severe chronic neuropathic or mixed pain.

Recruitment & Eligibility

Status: Completed

Sex: Not specified

Target Recruitment: 18

Inclusion Criteria

1. informed consent
2. 3 months - 18 years of age
3. meet the diagnostic criteria for neuropathic or mixed pain
4. chronic pain defined as the recurrent or continuous pain persisting more than 3 months
5. at least moderate pain as defined by average pain intensity of *4 /10
6. Stable underlying disease condition and treatment
7. For oncology patients: clinical remission or no expected changes in therapeutic protocol

Exclusion Criteria

1. Pain duration of more than 5 years
2. Current use of gabapentin or tramadol for treatment of neuropathic pain or exposure in the year before screening for the GABA-1 study.
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 diagnosis of sickle cell disease.
6. Subjects that present significant cognitive impairment.
7. 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.
8. Subjects with history of suicidal ideation or behaviour.
9. Subjects under prohibited concomitant medication (refer to specific protocol section 6.6.2 *Prohibited medications*).
10. 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.
11. Subjects aged 3 months to less than 18 years old with a body mass index (BMI) for age and gender of < 5th percentile or > 95th percentile (charts provided as Appendix 5).
12. Subjects with glomerular filtration rate < 90 mL/min/1.73 m2 (Schwarz equation).
13. Subjects with significant hepatic impairment with Aspartate Transaminase (AST) and Alanine Transaminase (ALT) enzymes 3 times the upper limit of the age-specific reference range.
14. Subjects with known allergy, hypersensitivity or clinically significant intolerance to gabapentin or tramadol or any component found in the study drugs.
15. Subjects with clinically relevant abnormal ECG at the screening visit in the discretion of the investigator/cardiologist.
16. Subjects participating in another clinical interventional trial.
17. Subjects scheduled for surgery or in recovery from surgery occurring within 3 months of baseline assessment.
18. Female subjects who are pregnant or currently lactating.
19. Subjects that failed screening or was previously enrolled in this study.

Study & Design

Study Type: Interventional

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
<p>Average pain score at the end of the treatment period (average of 2 measures<br /><br>each day for 3 days before end of study visit, V10) as assessed by<br /><br>age-appropriate pain scales (FLACC, FPS-R, NRS-11).</p><br>

Secondary Outcome Measures

Name	Time	Method