CBD oil tested for breast cancer drug side effect

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Documented informed consent of the participant * Age: ≥ 18 years * Eastern Cooperative Oncology Group (ECOG) ≤ 2 * Postmenopausal by last menses \> 12 months or medically induced menopause in premenopausal women for AI therapy use * At least 5 years since other malignancy except adequately treated basal cell or squamous cell skin cancer, in situ cervical cancer, or adequately treated stage I or II cancer from which the patient is currently in complete remission * Ability to read and understand English, Spanish, or translations by interpreters for questionnaires * Histologically confirmed primary invasive adenocarcinoma of the breast or ductal carcinoma in situ of the breast * Stage 0, I, II, or IIIA disease * No metastatic disease * Must have undergone definitive breast cancer surgery and recovered * Must have completed adjuvant chemotherapy as applicable, including systemic chemotherapy, anti-HER2 therapy, and/or radiation therapy * Estrogen-receptor positive (ER+) and/or progesterone-receptor positive (PR+) * Currently taking a third-generation aromatase inhibitor (AI) (e.g., anastrozole \[Arimidex (registered trademark)\], letrozole \[Femara (registered trademark)\], or exemestane \[Aromasin (registered trademark)\]) for ≥ 90 days prior to registration with plans to continue for ≥ 180 days after registration * Must have a worst pain/stiffness of ≥ 4 on the Brief Pain Inventory (BPI) (item #2) that has started or increased with AI therapy Exclusion Criteria: * \< 3 months since prior cannabinoid containing cannabis or hemp products including CBD, tetrahydrocannabinol (THC), Marinol, and Epidiolex and must agree to refrain from use from sources outside of this study * \< 28 days since prior investigational agents * Medical therapy, alternative therapy, or physical therapy for joint pain/stiffness within the past 30 days * Narcotic use within 14 days of registration * Patients may have received corticosteroid treatment; however, the following criteria apply: * Patients must not have received oral or intramuscular corticosteroids within 28 days prior to registration * Patients must not have received intra-articular steroids to the study, or any other, joint within 28 days prior to registration * Patients must not have received topical analgesics (e.g., capsaicin preparations) to the study joint or any other analgesics (e.g., opiates, tramadol; with exception of nonsteroidal anti-inflammatory drugs \[NSAIDs\] and acetaminophen) within 14 days prior to registration * History of bone fracture or surgery of the afflicted hands, knees, and/or other joints within 6 months prior to registration * Any uncontrolled illness including ongoing or active infection * Known allergies or contraindications to cannabis * Significantly impaired hepatic function (alanine aminotransferase \[ALT\] \> 5 x upper limit of normal \[ULN\] or total bilirubin \[TBL\] \> 2 x ULN) OR the ALT or aspartate aminotransferase (AST) \> 3 x ULN and TBL \> 2 x ULN (or international normalized ratio \[INR\] \> 1.5 * Grade 3+ renal impairment * Clinically significant lab abnormalities in ALT, AST, total bilirubin, hemoglobin, hematocrit, or creatinine or any other laboratory tests that in the opinion of the investigator would prevent the patient from safely participating in the study * Having current thoughts of suicide or self-harm or history of suicidal ideation or attempted suicide * Meeting Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-V) criteria for current major psychiatric illness, such as bipolar disorder, major depression, or psychosis (including schizophrenia and affective psychosis) * History of seizure disorder * Concomitant administration with drugs that may interact adversely with CBD including warfarin, theophylline, amiodarone, anti-epileptic (e.g., clobazam, stiripentol, valproate, topiramate), anticonvulsant (e.g., diazepam, lamotrigine, phenytoin, ethosuximide, oxcarbazepine, pregabalin, tigabine, gabapentin); 3) barbiturate (e.g., phenobarbital, hexobarbital), benzodiazepine (e.g, chlordiazepoxide, clonazepam), opioid/narcotic (e.g, codeine, morphine) * Concomitant administration of cyclin-dependent kinase 4/6 inhibitors, such as abemaciclib, with AI therapy * Following a physical examination, the patient has any abnormalities that, in the opinion of the investigator would prevent the patient from safely participating in the study * Other active malignancy * Any other condition or medication use that would, in the Investigator's judgment, contraindicate the patient's participation in the clinical study due to safety concerns with clinical study procedures * Participants unwilling to abstain from donation of blood during the study * Participants who plan to travel outside of the United States during the study period * Women with childbearing potential are not eligible to participate. The study is for postmenopausal women taking aromatase inhibitors for adjuvant endocrine therapy * Participants with cognitive impairment are excluded due to dose titration instructions and completion of questionnaires * Prospective participants who, in the opinion of the investigator, may not be able to comply with all study procedures (including compliance issues related to feasibility/logistics)