Abuse Potential of Gabapentin Taken Orally Concomitantly With Oxycodone Hydrochloride in Healthy, Non-Drug-Dependent, Recreational Opioid Users

A Phase 4, Randomized, Double-Blind, Placebo and Active-Controlled, Single-Dose, Six-Way Crossover Study Evaluating the Abuse Potential of Gabapentin Taken Orally Concomitantly With Oxycodone Hydrochloride in Healthy, Non-Drug- Dependent, Recreational Opioid Users

The purpose of the present study is to assess prospectively the abuse potential of gabapentin when taken with and without oxycodone compared to placebo in healthy non-drug-dependent recreational opioid drug users under fasted condition.

Study Overview

• Status: Recruiting
• Conditions: Healthy, Non-Drug- Dependent, Recreational Opioid Users
• Intervention / Treatment: Drug: Placebo; Drug: Oxycodone 20mg; Drug: gabapentin 600 mg; Drug: Gabapentin 1200mg; Drug: Gabapentin 600 mg + Oxycodone 20 mg; Drug: Gabapentin 1200 mg + Oxycodone 20 mg

Detailed Description

This study consists of a Screening Visit (Visit 1), followed within 28 days by a Qualification Phase (Visit 2) which will require inpatient stay at the clinical research unit (CRU) for 3 nights. After a washout of at least 4 days, eligible participants will enter the Treatment Phase which will include 6 treatment periods with each dosing day separated by a washout period of at least 4 days. Participants will remain residential at the CRU from admission to the Qualification Phase through to completion of the assessments of the last treatment period in the Treatment Phase (approximately 28 days). A follow-up visit (Visit 3) will be scheduled from 7 to 14 days after the administration of the final dose of investigational product.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Dik Ng; Phone Number: (+44) 1304626895; Email: Dik.Ng@viatris.com

Study Locations

• United States
  • Kansas
    • Overland Park, Kansas, United States, 66212
      • Recruiting
      • Dr. Vince Clinical Research
      • Contact: William Lavery; Phone Number: (913) 333-3000; Email: wlavery@drvince.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Male and female participants must be 18 to 55 years of age, inclusive, at the time of screening. Participants must meet reproductive criteria as outlined in the protocol.
2. Male and female participants who are overtly healthy. Healthy is defined as no clinically relevant abnormalities identified by a detailed medical history, complete physical examination, vital signs, 12-lead ECG, and/or clinical laboratory tests.
3. Participants must have drug abuse experience with opioids; ie, must have used opioids for non-therapeutic purposes (ie, for psychoactive effects) on at least 10 occasions within the last year and at least once in the 12 weeks before the Screening Visit (Visit 1).
4. Participants must satisfactorily complete both the Naloxone Challenge and the Drug Discrimination.
5. Participants who are willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations, and other study procedures.
6. Body mass index (BMI) of 17.5 to 34 kg/m2, inclusive; and a total body weight ≥50 kg (110 lb).
7. Capable of giving signed informed consent as described in the protocol, which includes compliance with the requirements and restrictions listed in the informed consent document (ICD) and in this protocol.

Exclusion Criteria:

1. Participants with current or past diagnosis of any type of drug dependence within the past year. Diagnosis of substance and/or alcohol dependence (excluding caffeine and nicotine) will be assessed by the Investigator using the Diagnostic and Statistical Manual 5-Text Revision (DSM 5-TR) criteria performed at Screening. Current drug use will be allowed if the candidate can produce a negative urine sample excluding tetrahydrocannabinol (THC) prior to first dose and are free of any signs/symptoms of withdrawal. The candidate will be informed if they have a positive breathalyzer test or urine ethanol test.
2. Participants who are heavy smokers (>20 cigarettes equivalents per day).
3. Participants who are unable to abstain from smoking for at least 2 hours before and at least 8 hours after study drug administration.
4. Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurological, or allergic disease (including drug allergies, but excluding untreated, asymptomatic, seasonal allergies at the time of dosing).
5. Patients with any history of sleep apnea, myasthenia gravis and glaucoma.
6. Any condition or surgery possibly affecting drug absorption (e.g., gastrectomy) excluding cholecystectomy.
7. Abnormal baseline end-tidal carbon dioxide (EtCO2) <35mm Hg or >45 mm Hg.
8. Participants with a positive test for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), or hepatitis C antibody (HCVab).
9. Participants with active suicidal ideation or suicidal behavior within 5 years prior to Screening as determined through the use of the Columbia Suicide Severity Rating Scale (C SSRS) or active ideation identified at Screening or on Day -1.
10. Other acute or chronic medical or psychiatric condition including recent (within the past year) or active suicidal ideation or behavior or laboratory abnormality that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigator, would make the participant inappropriate for entry into this study.
11. Use of prescription or nonprescription drugs and dietary supplements within 7 days or 5 half lives (whichever is longer) prior to the first dose of investigational product. (Refer to Section 6.8 for additional details).
12. Herbal supplements and herbal medications must be discontinued at least 14 days prior to the first dose of study medication.
13. Previous administration with an investigational drug within 30 days (or as determined by the local requirement) or 5 half lives (whichever is longer) prior to screening.
14. Positive urine drug screen (UDS) for substances of abuse at admission to the Qualification Phase, excluding tetrahydrocannabinol (THC).
15. Participants who are unable to abstain from using THC during the inpatient stays in the Qualification and Treatment Phases of the study.
16. Has participated in, is currently participating in, or is seeking treatment for substance and/or alcohol related disorders (excluding nicotine and caffeine). If participation in a rehabilitation program was court-mandated as part of a plea agreement, entry may be permissible at the Investigator's discretion.
17. Has a positive urine ethanol test at Screening or upon admission to the study center.
18. Screening sitting blood pressure (BP) ≥145 mm Hg (systolic) or ≥95 mm Hg (diastolic), following at least 5 minutes rest.
19. Baseline (screening) 12 lead ECG that demonstrates clinically relevant abnormalities that may affect participant safety or interpretation of study results.
20. Participants with abnormalities in clinical laboratory tests for liver function tests at screening if deemed to be clinically significant in the opinion of the investigator.
21. Blood donation (excluding plasma donations) of approximately 1 pint (500 mL) or more within 56 days prior to dosing.
22. History of sensitivity to heparin or heparin induced thrombocytopenia.
23. History of hypersensitivity to gabapentin or oxycodone or any of the components in the formulation of the study products.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

6

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Treatment Phase C	Drug: gabapentin 600 mg; Gabapentin 600 mg
Active Comparator: Treatment Phase D	Drug: Gabapentin 1200mg; Gabapentin 1200mg
Placebo Comparator: Treatment Phase A	Drug: Placebo; Placebo
Active Comparator: Treatment Phase B	Drug: Oxycodone 20mg; oxycodone 20mg
Active Comparator: Treatment Phase E	Drug: Gabapentin 600 mg + Oxycodone 20 mg; Gabapentin 600 mg + Oxycodone 20 mg
Active Comparator: Treatment Phase F	Drug: Gabapentin 1200 mg + Oxycodone 20 mg; Gabapentin 1200 mg + Oxycodone 20 mg

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Bipolar Visual Analog Scale (VAS) for "Drug Liking" Maximum Effect (Emax)	Drug Liking assesses how much a participant likes or dislikes a drug effect at the time the question is being asked. It is scored using a 100 mm visual analogue scale (VAS), where 0 mm = "Strong Disliking", 50 mm = "Neither Like nor Dislike", and 100 mm = "Strong Liking"	Up to 24 hours after treatments

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Bipolar VAS for "Drug Liking" (Time for Emax [TEmax])	Time after dosing when the maximum effect for Drug Liking VAS is reached	Up to 24 hours after treatments
Unipolar VAS for "High" (Maximum Effect, Emax)	Maximum effect on the 100 mm visual analog scale for the question "I am feeling high" where 0 = "not at all" and 100 = "extremely"	Up to 24 hours after treatments
Unipolar VAS for "High" (Time for Emax [TEmax])	Time after dosing when the maximum effect for "High" VAS is reached	Up to 24 hours after treatments
Bipolar VAS for "Take Drug Again"	100 mm visual analog scale for the question "I would take this drug again" where 0 = "definitely not", 50 = "neutral", and 100 = "definitely so".	at 12 and 24 hours after treatments
Bipolar VAS for "Drug Liking" (Area Under the Effect-time Profile From Time 0 to the Time of the Last Quantifiable Effect [AUEClast])	Area under the effect-time profile from time 0 to the time of the last available data for the "Drug liking" visual analog scale which assesses how much a participant likes or dislikes a drug effect at the time the question ("at this moment, my liking this drug is") is being asked. It is scored using a 100 mm visual analogue scale (VAS), where 0 mm = "Strong Disliking", 50 mm = "Neither Like nor Dislike", and 100 mm = "Strong Liking". The minimum and maximum possible scores are approximately 0 and 2400 if a subject scores 0 mm (strong disliking) and 100 mm (strong liking) respectively at every timepoint up to 24 hours.	Up to 24 hours after treatments (Assessments were made at the following timepoints after each treatment: 0, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12 and 24hours)
Unipolar VAS for "High" (Area Under the Effect-time Profile From Time 0 to the Time of the Last Quantifiable Effect [AUEClast])	Area under the effect-time profile from time 0 to the time of the last available data for the "High" visual analog scale which measures on a 100 mm visual analog scale the subject's response to the question "I am feeling high" where 0 = "not at all" and 100 = "extremely". The minimum and maximum possible scores are 0 and approximately 2400 if a subject scores 0 mm (not at all) and 100 mm (extremely) respectively at every timepoint up to 24 hours.	Up to 24 hours after treatments (Assessments were made at the following timepoints after each treatment: 0, 0.25, 0.5,1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12 and 24 hours)
Bipolar VAS for "Overall Drug Liking"	100 mm visual analog scale for the question "Overall, my liking for this drug is" where 0 = "definitely not", 50 = "neutral", and 100 = "definitely so".	at 12 and 24 hours after treatments
Pupil size (diameter) change for baseline from Maximum Effect		Up to 24 hours after treatments (Assessments were made at the following timepoints after each treatment: 0, 0.25, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 12 and 24 hours)

Collaborators and Investigators

• Sponsor: Viatris Inc.
• Collaborators: Dr. Vince Clinical Research

Study record dates

Study Major Dates

• Study Start (Actual): August 3, 2026
• Primary Completion (Estimated): January 31, 2027
• Study Completion (Estimated): February 14, 2027

Study Registration Dates

• First Submitted: September 4, 2026
• First Submitted That Met QC Criteria: September 4, 2026
• First Posted (Actual): September 10, 2026

Study Record Updates

• Last Update Posted (Actual): September 10, 2026
• Last Update Submitted That Met QC Criteria: September 4, 2026
• Last Verified: September 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Amino Acids, Peptides, and Proteins; Organic Chemicals; Heterocyclic Compounds; Heterocyclic Compounds, Fused-Ring; Hydrocarbons; Cyclohexanes; Cycloparaffins; Hydrocarbons, Alicyclic; Hydrocarbons, Cyclic; Acids, Acyclic; Carboxylic Acids; Alkaloids; Polycyclic Aromatic Hydrocarbons; Polycyclic Compounds; Amines; Amino Acids; Heterocyclic Compounds, 4 or More Rings; gamma-Aminobutyric Acid; Aminobutyrates; Butyrates; Acids, Carbocyclic; Morphinans; Opiate Alkaloids; Heterocyclic Compounds, Bridged-Ring; Phenanthrenes; Morphine Derivatives; Cyclohexanecarboxylic Acids; Codeine; Gabapentin; Oxycodone
• Other Study ID Numbers: GABA-TBZ-4001

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No