Coadministration has not been studied. Ibuprofen is metabolised mainly by CYP2C9 and to a lesser extent by CYP2C8 and direct glucuronidation. Doravirine is metabolized by CYP3A4 and does not inhibit or induce CYP or UGT enzymes. Emtricitabine and tenofovir are eliminated renally. No pharmacokinetic interaction is expected with doravirine and lamivudine. However, ibuprofen could potentially decrease renal elimination of tenofovir as in vitro data suggest that ibuprofen inhibits the renal transporters OAT1 (moderate inhibition) and MRP4 which are involved in tenofovir excretion. No a priori dose adjustment is recommended. Coadministration could potentially result in increased risk of nephrotoxicity. The risk is increased if an NSAID is used for a long duration, if the patient has a pre-existing renal dysfunction, has a low body weight, or receives other drugs that may increase tenofovir exposure. Cases of acute renal failure after initiation of high dose or multiple NSAIDs have been reported in patients treated with tenofovir-DF and with risk factors for renal dysfunction. Alternatives to NSAIDs should be considered in patients at risk for renal dysfunction. If tenofovir-DF is co-administered with an NSAID, renal function should be monitored adequately.