Metformin Hydrochloride in Treating Patients With Prostate Cancer Undergoing Surgery

Inclusion Criteria:

* Men will be eligible to this study if they are diagnosed with a histologically confirmed organ-confined adenocarcinoma of the prostate (PCa) treatable by prostatectomy and have a current PSA less than 50 ng/ml
* Have not received chemotherapy and/or radiation for any malignancy (excluding non-melanoma skin cancer and cancers confined to organs with removal as only treatment) in the past 5 years
* Eastern Cooperative Oncology Group (ECOG) performance status 0-1 (Karnofsky \>= 70%)
* Leukocytes \>= 3,000/uL
* Absolute neutrophil count \>= 1,500/uL
* Platelets \>= 100,000/uL
* Total bilirubin =\< 1.5 times institutional upper limits of normal (ULN)
* Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase \[SGPT\]) =\< 1.5 times institutional ULN
* Creatinine within normal institutional limits
* Willing to use adequate contraception (barrier method, abstinence, subject has had a vasectomy or partner is using effective birth control or is postmenopausal) for the duration of study participation
* Ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

* Type I or type II diabetic patients on treatment with any drug for diabetes or participants with fasting glucose \>= 126 mg/dL
* History of impaired liver or kidney function
* Participants with a current history of high alcohol consumption (\> 3 standard drinks/day) or binge drinking (5 or more drinks) in one session of 1-3 hours
* History of lactic acidosis or at increased risk for lactic acidosis such as patients with unstable or acute congestive heart failure who are at risk of hypoperfusion with hypoxemia
* Participants may not be receiving any other investigational agents
* History of allergic reactions attributed to compounds of similar chemical composition to metformin
* 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
* History of acute or chronic metabolic acidosis
* Concurrent use of cationic drugs (e.g., amiloride, digoxin, morphine, procainamide, quinidine, quinine, ranitidine, triamterene, trimethoprim, or vancomycin)
* Concurrent use of non-study metformin or other biguanides