Omeprazole with Cabazitaxel or Docetaxel for Prostate Cancer

Inclusion Criteria: * Patients must have castrate refractory prostate cancer with prior docetaxel treatment which was used in the castrate refractory setting * Cancer Progression as defined by prostate cancer working group 3 (PCWG3) any type- prostate specific antigen only, bone only +nodal, nodal only or new lesions * Age 18 or older. * ECOG 0, 1, or 2 * Life expectancy of greater than 2 months * Men must agree to use adequate contraception (barrier method of birth control; abstinence) prior to study entry and for three (3) months after study treatment discontinuation. * Ability to understand and the willingness to sign an IRB-approved informed consent document (either directly or via a legally authorized representative). * Organ \& marrow function as defined below: Absolute neutrophil count \>1,200/mcL, Platelets \>75,000/mcL; total bilirubin = within normal institutional limits; AST(SGOT)/ALT(SGPT) \<2.5 X institutional upper limit of normal; creatinine \<2.5 X institutional upper limit of normal Exclusion Criteria: * Patients may not be receiving any other investigational agents. * History of allergic reactions attributed to compounds of similar chemical or biologic composition to omeprazole or taxane therapy. * Uncontrolled intercurrent illness including, but not limited to ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.