Probenecid-d14 is intended for use as an internal standard for the quantification of probenecid by GC- or LC-MS. Probenecid is a benzoic acid derivative that inhibits organic anion transporters (OATs) but activates the transient receptor potential (TRP) channel TRPV2. It inhibits OAT1, OAT3, and OAT6 with Ki values of 6.3, 9.0, and 8.4 µM, respectively, as well as OAT2 with an IC50 value of 0.67 µM. It is a poor inhibitor of the organic cation transporters OCT1 and OCT2 (IC50 = 1.6 and 1.7 mM, respectively). It also acts as an agonist of TRPV2 (EC50 = 31.9 µM), eliciting nociceptive behavior under inflammatory conditions in mice. Formulations containing probenecid have been used in the treatment of gouty arthritis.