The reduced dose tenofovir (Viread) Of 150mg a day appears to be a safe and effective treatment for people with HIV and who have moderate renal impairment, the researchers in Thailand report in the online edition of ClinicalInfectious Diseases. The daily dose of 150mg from the drug exposure similar to the recommended dose 300 mg every 48 hours. Moreover, treatment with the reduced dose maintains viral suppression.
"This is the first alternative assessment report to dose TDF [tenofovir] in HIV-infected adults with moderate renal impairment. Our data demonstrate that a dose reduction of TDF approved 300 mg every 48 hours in adults with a creatinine clearance between 30% to <50 ml / min for 150mg once daily provides comparable exposures over a period of hours 48 after receiving a NNRTI [reverse transcriptase inhibitors non-nucleoside] - or lopinavir / ritonavir - therapy ", comment the authors. "Preservation of viral suppression and lack of adverse events was reassuring".
Tenofovir is a widely used antiretroviral. The standard dose is 300 mg once daily in combination with other antiretroviral drugs. The drug is secreted through the kidneys. A pharmacokinetic study in HIV-negative patients people with impaired renal function has shown that subjects with a creatinine clearance less than 50 ml / min was significantly higher blood levels of tenofovir. Consequently, it was calculated that tenofovir dose 300 48 mg every hour for people with moderate renal impairment - creatinine clearance between 30-49ml / min - Exposure to drugs that offer similar to what is observed in persons with normal renal function receiving 300mg the standard daily dose.
But many people senter that the administration of this dosage every 48 hours, is confusing and inconvenient.
Tablets (150, 200, 250mg) have recently been approved for people with lower resistance to tenofovir. The hypothesis formulated by the researchers is that treatment with 150mg once a day, offers the same drug exposure at the recommended dose of 300 mg for each period of 48 hours for adults with moderate renal impairment,
In phase I, open the pharmacokinetic study of 40 people living with HIV who had creatinine clearance between 30 and 50 ml / min, who were taking a tenofovir dose mg every 300 48 hours. All had their viral loads undetectable brought to the point; half of them were taking a combination based on an NNRTI and other 50% of a regimen containing lopinavir / ritonavir.
Blood levels of tenofovir were scrutinized extensively over a period of 48 hours, and intracellular exposure to tenofovir was also monitored in peripheral blood mononuclear cells. The study subjects then were connected to a 150mg dose / day of tenofovir. After two weeks, the pharmacokinetic analysis was repeated.
The participants had a mean age of 56 years and an average weight of 51kg. Mean creatinine clearance was 43,9 min / ml, serum creatinine and the median was 1,3 mg / dl. All had an undetectable viral load and CD4 average count was 502 cells / mm3.
The mean plasma concentrations of tenofovir were essentially similar for the groups that received 300 and the groups that received 150mg, regardless of participants are taking the drug in combination with a NNRTI or ritonavir and lopinavir.
In general, people taking lopinavir / ritonavir, tenofovir had a conventração in higher plasma levels than people taking an NNRTI. This was observed with both 300 groups and the 150mg tenofovir.
The intracellular concentrations of tenofovir were comparable between the two groups; the 300mg and the 150mg.
"The data show that the PTO switch to 150mg once a day in HIV-infected adults with moderately impaired renal function leads to comparable exposure to current recommended 300mg, each 48 hours," the authors conclude. "This daily dose is an option for this subpopulation of patients, and it may be preferable to simplify their antiretroviral regimens and to facilitate adherence. However, renal function should continue to be closely monitored in these patients. "
Published: 22º May 2015
Translated from the original in EnglishLower daily dose of tenofovir 150mg safe and effective in people with moderate renal impairmentby Cláudio Santos de Souza: "Yesterday, escondíamo us to survive! Today, shown ourselves to live!
Cressey TR et al.Intracellular and plasma pharmacokinetics of tenofovir disoproxil fumarate (TDF) 300mg each 48 hours versus 150mg / day in HIV-infected adults with moderate renal impairment. Clin infect Dis, online edition, up to 2015.
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