Dronabinol Opioid Sparing Evaluation (DOSE) Trial

This study will be a 12-week, open-label trial that is designed to evaluate the Opioid-Sparing effect of Dronabinol at ranging doses when coadministered with the opioid analgesics that are currently being prescribed to patients for their chronic pain condition. The purpose of this trial will be to assess the effectiveness of Dronabinol when combined with opioid analgesics to relieve pain at lower opioid doses and to evaluate any reduction of opioid-related side effects. Participants will take the study-drug, Dronabinol, along with their regular prescribed opioids and the results will be evaluated and analyzed according to defined endpoints.

Week one of the study is a Baseline Period during which time, baseline data related to opioid dose and frequency, mood, sleep, bowel movements, and pain intensity will be collected. Participants will receive no Dronabinol during week one and will continue to take their stabilized dose of regular prescribed opioids, both baseline and rescue.

Weeks two through four is the Titration Period, during which time study participants will titrate the Dronabinol dose up to a daily dose of 20 mg of Dronabinol per day, according to a prearranged titration table. Participants will continue to take their stabilized dose of regular prescribed opioids, both baseline and rescue. Participants will be encouraged to maintain the 20mg daily total dose of Dronabinol. Participants may also reduce their dose of Dronabinol at any time (if they experience severe adverse effects) to a minimum daily dose of Dronabinol of 10mg per day. Participants who cannot tolerate at least a minimum daily dose of 10mg of Dronabinol per day will be discontinued from the study.

Weeks five through twelve is the Opioid-Sparing Period, during which time participants will be encouraged to maintain the stabilized dose of Dronabinol that they "found" during the Study-Drug Dose Finding Period. Study Participants will continue to take their regular prescribed opioids, but will be encouraged to reduce their opioid dose and/or opioid dose frequency at any time during the remainder of the study should they experience a reduction in pain and/or an improvement in opioid-related side effects.

Eligibility Criteria:
Inclusion Criteria:

1. Ability to read, speak, and understand English;
2. Provision of signed and dated informed consent form;
3. Stated willingness to comply with all study procedures and availability for the duration of the study;
4. Male, Female, or Transgender aged \> 18;
5. In fair and stable general health as evidenced by medical history and physical examination, and confirmed by prescriber;
6. Participants who have been diagnosed with a pain condition that has not adequately responded to other treatments, in the judgement of the provider;
7. Participants who are currently taking a stabilized dose of opioid analgesics, and who have been taking opioid analgesics for at least 3-months, and who report a score of \> 3 on the Brief Pain Inventory 0-10 severity index.;
8. Ability to take medications as prescribed and willingness to adhere to the study-drug regimen;
9. For females of reproductive potential: use of highly effective contraception for at least 1 month prior to enrollment and agreement to use such a method during study participation;
10. Agreement to abstain from the use of cannabis or other cannabinoid compounds, other than the study-drug Dronabinol, throughout study duration;

Exclusion Criteria:

1. Current substance abuse by self-report;
2. Current use of cannabis or other cannabinoid compounds;
3. Significant baseline nausea, vomiting, sedation, or other symptoms reported by physician and or patient that may compromise the collection of study-related data;
4. A history of seizures, head trauma, and or mental illness ;
5. Pregnancy or lactation;
6. Known allergic reactions to components of Dronabinol;
7. Taking any of the following drugs:

Strong CYP2C9 Inhibitor (e.g., amiodarone, fluconazole) Strong CYP3A4 Inhibitor (e.g., ketoconazole, itraconazole, clarithromycin, ritonavir, erythromycin) Potent CYP2C9 or CYP3A4 inducers (e.g., rifampicin) Drugs that are highly protein-bound (e.g., warfarin, cyclosporine, amphotericin B)