Nephrotoxicity of HAART

Abstract

Highly active antiretroviral therapy (HAART) and other medical therapies for HIV-related infections have been associated with toxicities. Antiretroviral therapy can contribute to renal dysfunction directly by inducing acute tubular necrosis, acute interstitial nephritis, crystal nephropathy, and renal tubular disorders or indirectly via drug interactions. With the increase in HAART use, clinicians must screen patients for the development of kidney disease especially if the regimen employed increases risk of kidney injury. It is also important that patients with chronic kidney disease (CKD) are not denied the best combinations, especially since most drugs can be adjusted based on the estimated GFR. Early detection of risk factors, systematic screening for chronic causes of CKD, and appropriate referrals for kidney disease management should be advocated for improved patient care. The interaction between immunosuppressive therapy and HAART in patients with kidney transplants and the recent endorsement of tenofovir/emtricitabine by the Centers for Disease Control (CDC) for preexposure prophylaxis bring a new dimension for nephrotoxicity vigilance. This paper summarizes the common antiretroviral drugs associated with nephrotoxicity with particular emphasis on tenofovir and protease inhibitors, their risk factors, and management as well as prevention strategies.

Figure 1

Tenofovir is predominantly eliminated via a combination of glomerular filtration and active tubular secretion. It enters into the kidney cell from the basolateral side via organic anion transporters, OAT-1 and OAT-3 [44], and leaves either via P glycoprotein, MRP2, and/or MRP4 [45]. Inhibition of MRP4 by PI/RTV leads to increased intracellular tenofovir levels which may increase its nephrotoxic effects. OAT: organic anion transporter; MRP: multidrug resistant protein; PI/RTV: ritonavir-boosted protease inhibitor; TFV: tenofovir.