I have seen some confusion about Tenofovir (Viread, which is in Truvada and Atripla) dosing in those with kidney problems in my pozhealth at yahoogroups.com list, so I am posting this information.
So far, most of the problems with tenofovir and kidney function have been reported in treatment experienced patients on boosted protease inhibitors, african americans, people with diabetes, or those using other medications that may affect the kidneys. Naive patients on Atripla seem to be doing just fine.
By the way, for those of you who have not calculated your creatinine clearance, ask your doctor if that value is included in your lab report. If not , ask him or her to include it. You can also calculate it here:
Dosage of tenofovir should be adjusted in adults with creatinine clearances less than 50 mL/minute. The manufacturer and some experts recommend that adults with creatinine clearances of 30 to 49 mL/minute should receive 300 mg of tenofovir once every 48 hours and those with clearances of 10 to 29 mL/minute should receive 300 mg twice weekly. Adults undergoing hemodialysis should receive 300 mg of tenofovir once every 7 days (based on 3 hemodialysis sessions per week, each lasting approximately 4 hours) or 300 mg after a total of approximately 12 hours of dialysis; the dose should be administered following completion of a dialysis session. Because safety and efficacy of these dosages have not been evaluated in clinical studies, clinical response to treatment and renal function should be closely monitored. The manufacturer states that dosage recommendations cannot be made for adults with creatinine clearances less than 10 mL/minute who are not undergoing hemodialysis since the pharmacokinetics of the drug have not been studied in such patients.
The usual dosage of the fixed-combination preparation containing emtricitabine and tenofovir disoproxil fumarate (Truvada®) can be used in adults with creatinine clearances of 50 mL/minute or greater. The manufacturer of the fixed-combination preparation recommends a dosage of one tablet (200 mg of emtricitabine and 300 mg of tenofovir disoproxil fumarate) every 48 hours in adults with creatinine clearances of 30–49 mL/minute; response to therapy and renal function should be monitored in these patients since this dosing recommendation has not been evaluated in clinical studies. The fixed-combination preparation should not be used in adults with creatinine clearances less than 30 mL/minute, including those undergoing dialysis.
The usual dosage of the fixed-combination preparation containing tenofovir disoproxil fumarate, emtricitabine, and efavirenz (Atripla®) can be used in adults with creatinine clearances of 50 mL/minute or greater. The fixed-combination preparation should not be used in adults with creatinine clearances less than 50 mL/minute.
Dosage adjustment is not necessary in patients with hepatic impairment