Drug Interactions between AccessPak for HIV PEP Basic and aztreonam

MONITOR: Coadministration of tenofovir with other drugs that are also eliminated by active tubular secretion may result in increased plasma concentrations of tenofovir and/or the coadministered drug(s) due to competition for renal excretion. Drugs that are thought to undergo active tubular secretion include acyclovir, amiloride, cidofovir, cimetidine, flecainide, ganciclovir, metformin, midodrine, procainamide, quinidine, ranitidine, triamterene, valacyclovir, and valganciclovir.

MANAGEMENT: Patients receiving tenofovir in combination with other drugs that undergo active tubular secretion should be monitored for excessive pharmacologic effects of all drugs, and the dosages adjusted as necessary. Because tenofovir is associated with dose-related nephrotoxicity, especially proximal renal tubulopathy, renal function tests including serum creatinine, serum phosphorous, estimated creatinine clearance, urine glucose, and urine protein should be performed prior to and during therapy. Patients with renal insufficiency at baseline or during treatment may require dosage adjustment in accordance with the manufacturer's product labeling. Persistent or worsening bone pain, pain in extremities, fractures, and/or muscular pain or weakness may also be manifestations of proximal renal tubulopathy and should prompt an evaluation of renal function in at-risk patients.