Addition of Probenecid to Penicillin-V Therapy

Inclusion Criteria: * Adult healthy volunteers (\>18 years old). * Previously taken penicillin-based antibiotics without allergic response. * Estimated Glomerular Filtration Rate (eGFR) \> 90. Exclusion Criteria: * Lacking capacity to consent. * Documented allergy to penicillin, other beta-lactam antibiotics, or probenecid. * History of G6PD Deficiency. * Known blood dyscrasias. * Anaemia (Hb \< 12g/dL female, 13g/dL males). * Abnormal liver function (ALT, AST, ALP or bilirubin \> ULN). * eGFR \< 90. * Pregnant or likely to become pregnant during study period. * Breastfeeding women. * Symptoms consistent with active infection. * History of gout or uric acid kidney stones. * Taking regular medication that may interact with probenecid including, but not limited to methotrexate, lorazepam, acetaminophen, oral hypoglycaemic medication, sulfa containing drugs, non-steroidal anti-inflammatory drugs. * History of evidence of any medical, neurological, or psychological condition that would expose the subject to an undue risk of a significant adverse event or interfere with study assessments during the course of the trial as determined by the clinical judgement of the investigator. * Recent involvement in other research (within prior 3 months).