Efavirenz, lamivudine, and tenofovir and Renal dysfunction

Patients with clinically significant renal impairment may be at greater risk for toxicities and adverse effects from nucleoside reverse transcriptase inhibitors (NRTIs) due to decreased drug clearance. Dosage adjustments are recommended. In addition, these patients should be monitored closely during NRTI therapy, and dosages adjusted further if necessary.

Tenofovir is primarily eliminated by the kidney via glomerular filtration and active tubular secretion. Renal impairment, including acute renal failure and Fanconi syndrome, has been reported with tenofovir use. Close monitoring of renal function and lengthening the dosing interval are recommended for patients with creatinine clearance less than 50 mL/min. Creatinine clearance should be calculated in all patients before starting tenofovir treatment and during treatment when clinically appropriate. Routine monitoring of serum creatinine and phosphorus is recommended for patients at risk of or with a history of renal dysfunction. Safety and effectiveness have not been evaluated in patients with renal insufficiency using dose adjustments; therefore, the benefit of tenofovir treatment should be weighed against the risk of renal toxicity. Tenofovir should be avoided in patients who are currently using or have recently used nephrotoxic drugs.