Clinical Research Directory

Inclusion Criteria: * Must be able to take capsules orally * Kidney transplant performed at a UCSF facility within the last 6 months * Most recent glomerular filtration rate (GFR) \>30 mL/min/1.73 m2 * Tolerated initial 6 months of post-transplant TMP-SMX (defined as no intentional periods of TMP-SMX cessation in first 6 months after transplant due to hyperkalemia, allergic reaction, or unexpected/excessive neutropenia) * Considered "high risk for UTI" after kidney transplant, as defined by one or more of the following: (1) Congenital anomaly of kidney/urinary tract as kidney failure etiology, (2) Diagnosis of neurogenic bladder and/or use of clean intermittent catheterization and/or nightly continuous urinary drainage, (3) Diabetes mellitus (diagnosed either prior to or new-onset after transplant), (4) History of recurrent UTIs as diagnosed by a provider prior to transplant, (5) Occurrence of any UTI in first 6 months after transplant, (6) Delayed graft function (defined as need for dialysis within 7 days of transplant) Exclusion Criteria: * History of intolerance or allergy to trimethoprim (TMP) and/or sulfamethoxazole (SMX) * History of UTI due to a TMP-SMX-resistant organism in the first 6 months after transplant * Moderate or severe neutropenia (absolute neutrophil count \<1,000 cells/μL) on most recent bloodwork available at the time of recruitment * Uncontrolled hyperkalemia (serum potassium ≥5.0 mEq/L) on most recent bloodwork available at the time of recruitment * Provider-determined/documented need for either continuation or discontinuation of TMP-SMX prophylaxis that would preclude the patient's randomization * Current pregnancy * Incarcerated individuals/prisoners * Inability to provide informed consent or assent, and no legally authorized representative available