The supplemental opioid medication reflecting the standard of care was available as patient- or nurse-controlled intravenous (i.v.) morphine or hydromorphone. This supplemental opioid analgesic medication (SOAM) was given to control pain, as needed, in both the treatment and placebo groups.
Children and adolescents 6 months and older were dosed with a dose regimen of 1.25 mg/kg body weight for the first 24 hours of treatment. 24 hours after the start of study medication (and based on clinical judgment), a dose reduction to 1.0 mg/kg was allowed.
Participants 30 days to less than 6 months old were dosed with a regimen of 0.5 mg/kg for the first 24 hours of treatment. The dose of IMP could be reduced after 24 hours to 0.3 mg/kg (if there was a reduced need for analgesia according to the investigator's judgment).
Participants aged from birth to less than 30 days old were dosed with a regimen of 0.1 mg/kg for the first 24 hours of treatment. The dose of the IMP could be reduced after 24 hours to 0.075 mg/kg (if there was a reduced need for analgesia according to the investigator's judgment).
The decision to maintain or alter the dose based on the effectiveness of the analgesia (pain killer) and the adverse event profile observed in each participant over the first 24-hour dosing period was made based on the investigator's judgment.
In exceptional cases, if a participant had unbearable pain despite using nurse-controlled analgesia (NCA) or patient-controlled analgesia (PCA), an additional bolus (defined as a clinician bolus) of morphine or hydromorphone could have been administered. The clinician bolus could have been given either using the NCA/PCA pump system or by an intravenous bolus injection. The opioid given as a clinician bolus or if the NCA/PCA intravenous line failed, had to be the same opioid used in the NCA/PCA pump system.
Dosing with IMP was stopped if:
* A switch to exclusively oral opioid analgesic medication was indicated according to the local standard of care.
* Opioid analgesic medication was no longer needed.
* IMP had been administered for 72 hours.
Safety evaluations included assessment of adverse events, physical examination, vital signs, laboratory parameters, electrocardiogram, oxygen saturation, and, only for children older than 6 years of age, a scale to assess suicidal ideation (Columbia Suicide Severity Rating Scale \[C-SSRS\]). The maximum study duration for each participant was 42 days.
The evaluation of the safety and efficacy data was performed by age groups as aligned with European and United States agencies. Within the tapentadol treatment group, no analysis by tapentadol dose was conducted. Results for participants aged 2 years to \<18 years were provided to the Pediatric Committee of the European Medicines Agency (EU PDCO) before recruitment of the children less than 6-month old required for the US Food and Drug Administration \[FDA\] analysis was completed. Participants from birth to \<2 years old were analyzed separately for the US FDA only and not included in the analysis of the population aged from 2 years to \<18 years.
