Low Dose Naltrexone (LDN) for Management of Fatigue in Prostate Cancer Patients on Androgen Deprivation Therapy (ADT)

Inclusion Criteria

* Histologically or cytologically confirmed biochemical recurrence and on ADT for at least 3 months. Metastatic castrate-sensitive and castrate-resistant prostate cancer on ADT with or without novel hormonal therapy like apalutamide, darolutamide, enzalutamide and abiraterone.
* Initiation of hormonal ablative therapy within 3 months of registration.
* ECOG performance status \<3.
* Patients must have normal organ and marrow function as defined below:

  * leukocytes \>3,000/μL
  * absolute neutrophil count \>1,500/μL
  * platelets \>100,000/μL
  * total bilirubin within normal institutional limits
  * AST(SGOT)/ALT(SGPT) \<2.5 X institutional upper limit of normal
  * creatinine ≤2.5.0
  * left ventricular ejection fraction \>45%
  * FACIT-F score \< 43 on screening
* Ability to understand and the willingness to sign a written informed consent document.

Exclusion Criteria

* Prior chemotherapy received in the last three months.
* Patients currently on PARP inhibitors.
* Currently taking or have taken within 10 days of enrollment.
* Patients may not be receiving any other investigational agents.
* History of allergic reactions attributed to compounds of similar chemical or biologic composition to Naltrexone or other agents used in the study.
* History of other malignancies other than nonmelanoma skin cancer, unless in complete remission and off therapy for that disease for at least 5 years.
* Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, history of congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.
* Any Patient with acute hepatitis and liver failure are excluded.