Study has been updated with a new protocol number

The purpose of this study is to evaluate the safety, pharmacokinetics (PK), and effectiveness of Hydrocodone Bitartrate (HYD) tablets in children with moderate to severe pain requiring around-the-clock opioid analgesics.

Inclusion Criteria include:

1. Males and females, aged 12 to 17 years, with pain severe enough to require daily, around-the-clock opioid treatment at a dose equivalent to at least 20 mg daily of hydrocodone for at least 2 weeks.
2. Patients must have stable vital signs and hemoglobin oxygen saturation, eg, measured by pulse oximetry (SpO2).
3. Patients must be willing and able to swallow medicinal tablets.
4. Female patients of childbearing potential must have a negative pregnancy test within 24 hours prior to the start of study drug treatment.
5. Female patients who are sexually active must be using (and continue using throughout the study) an acceptable method of birth control, per investigator's discretion.
6. Patients and patient's parent/caregiver must be compliant with the protocol, ie, must be able to perform study assessments and understand and complete the age-appropriate scale to rate pain intensity.
7. Patients must not have a cognitive developmental delay or any other condition that would preclude them from completing the age-appropriate pain scale.

Exclusion Criteria include:

1. Patients who require a starting total daily dose of HYD > 120 mg.
2. Patients who have had surgery within 72 hours prior to the start of study drug treatment.
3. Patients who have any planned surgery during the study will be excluded.
4. Female patients who are pregnant or lactating.
5. Patients who are allergic to hydrocodone or any other component of HYD or have a history of allergies to other opioids.
6. Patients who receive or are expected to receive an investigational drug/therapy during the study drug treatment or follow-up period.
7. Patients who are anticipated to receive any hydrocodone- or hydromorphone-containing products (other than study drug) during the study or 3 days prior to initiation of treatment with study drug.
8. Patients with a history of alcohol, medication, or illicit drug abuse or addiction and/or opioid abuse or addiction at any time.
9. Patients with contraindication to blood sampling.

Other protocol-specific inclusion/exclusion criteria may apply.