A certain degree of renal toxicity is apparent in a few
HIV patients receiving therapy with tenofovir disoproxil fumarate [the active ingredient in Viread and one of the drugs found in Truvada and Atripla], but
overall the drug appears to be safe, according to a new study.
"The data is reassuring that the risk of renal toxicity, whilst
present, occurs at a low frequency," lead investigator Dr. Mark R.
Nelson told Reuters Health.
"Physicians should be reassured that although clinical monitoring
for renal abnormalities is essential in all HIV patients, no specific
measures need to occur with patients on tenofovir," he added.
In the June 19th issue of AIDS, Dr. Nelson of Chelsea and
Westminster Hospital, London and colleagues note that they examined a
database covering the first 4 years of tenofovir use.
Postmarketing safety surveillance revealed no new unexpected
toxicities. However, of 10,343 patients, serious adverse events were
reported in 631 (6%) and of these, 211 (2%) were considered to be
related to tenofovir.
Overall, 0.5% of patients experienced any type of renal serious
adverse event and acute or chronic renal failure was reported in 0.3%.
Elevated serum creatinine was seen in 2.2% of patients evaluated.
Baseline risk factors for the development of increased serum
creatinine during the study were elevated serum creatinine, concomitant
nephrotoxic medications, low body weight, advanced age, and lower CD4
cell count.
In particular, the team found that at baseline, 16% of patients were
taking a concomitant nephrotoxic medication, other than an antibiotic.
"Patients and physicians should be aware that a major risk factor
for tenofovir-associated renal abnormalities is the prescribing of
other nephrotoxic drugs," Dr. Nelson said.
He concluded that "good communication between HIV doctors and other
physicians to prevent prescribing of such medications is essential."
AIDS 2007;21:1273-1281.

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