Inclusion Criteria:
1. Is male or female aged between 2 and \<17 years.
2. Have a clinical indication of acute pain\* requiring hospitalization and multiple doses of parenterally administered nonopioid analgesic medication for at least 0.5 - 5 days.
3. Is either able to provide written informed consent or consent is provided from parents/legal guardians and assent provided from participants (where appropriate).
4. Is willing and able to remain at the study site for at least 12 hours and to attend a follow-up visit at 7 ± 2 days after the last dose of study drug.
5. Have negative HIV and hepatitis B \& C test results.
* Acute pain indications may include but are not limited to post-operative pain associated with musculoskeletal or soft tissue surgery, fractures or injury, or medical procedures.
Exclusion Criteria:
1. Has a known history of allergic reaction or clinically significant intolerance to acetaminophen, aspirin, opioids, or any nonsteroidal anti-inflammatory drugs (NSAIDs, including ibuprofen); history of NSAID-induced bronchospasm (subjects with the triad of asthma, nasal polyps, and chronic rhinitis are at greater risk for bronchospasm and should be considered carefully); or hypersensitivity, allergy, or significant reaction to sulfa (including sulfonamide) medicines, ingredients of the study drug, or any other drugs used in the study including anesthetics and antibiotics that may be required.
2. Has experienced any surgical complications or other issues that, in the opinion of the Investigator, could compromise the safety of the subject if he or she participates in the study or could confound the results of the study.
3. Has any clinically significant unstable cardiac, respiratory, neurological, immunological, hematological, or renal disease or any other condition that, in the opinion of the Investigator, could compromise the subject's welfare, ability to communicate with the study staff, or otherwise contraindicate study participation.
4. Has a history or current diagnosis of a significant psychiatric disorder that, in the opinion of the Investigator, would affect the subject's ability to comply with the study requirements.
5. Has a history of a clinically significant (Investigator opinion) gastrointestinal (GI) event within 6 months before screening or has any history of peptic or gastric ulcers or GI bleeding.
6. Has a surgical or medical condition of the GI or renal system that might significantly alter the absorption, distribution, or excretion of any drug substance.
7. Is considered by the Investigator, for any reason to be an unsuitable candidate to receive the study drug.
8. Is receiving systemic chemotherapy, has an active malignancy of any type, or has been diagnosed with cancer within 5 years before Screening (excluding treated squamous or basal cell carcinoma of the skin).
9. Is currently receiving anticoagulants (e.g. heparin or warfarin).
10. Has received a course of systemic corticosteroids (either oral or parenteral) within 3 months before screening (inhaled nasal steroids and regional/limited area application of topical corticosteroids (Investigator discretion) are allowed).
11. Has a history of chronic use (defined as daily use for \> 2 weeks) of NSAIDs, opiates, or glucocorticoids (except inhaled nasal steroids and regional/limited topical corticosteroids), for any condition within 6 months before study drug administration. Aspirin at a daily dose of ≤ 325 mg is allowed for cardiovascular prophylaxis if the subject has been on a stable dose regimen for ≥ 30 days before screening and has not experienced any relevant medical problem.
12. Has a significant renal or hepatic disease, as indicated by clinical laboratory assessment (results ≥ 3 times the upper limit of normal \[ULN\] for any liver function test, including aspartate aminotransferase \[AST\], alanine aminotransferase \[ALT\], or creatinine ≥ 1.5 times the ULN).
13. Has any clinically significant laboratory finding at screening that, in the opinion of the Investigator, contraindicates study participation.
14. Participated in another clinical study within 30 days before Screening.
15. Pregnant or lactating females
16. Sexually active females of childbearing potential not using adequate contraception\*\* and sexually active males not using adequate contraception\* \*\*Methods of contraception that are deemed adequate have failure rates of \< 1%, including: established use of oral contraceptives in conjunction with a barrier method of contraception; injected or implanted hormonal methods of contraception; placement of intrauterine device (IUD) or intrauterine system (IUS); sexual abstinence; hysterectomy; post-menopausal; sterilized; vasectomy. Suitable contraception should be used for the entire study period, from screening to follow-up. Women of childbearing age include all women that have begun puberty and had their first menstrual period until they reach menopause.
