icon-folder.gif   Conference Reports for NATAP  
  ICAAC 2015 55th Interscience Conference
on Antimicrobial Agents and Chemotherapy
September 5-9, 2015, San Diego, CA
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Over Half of NRTI Doses During Hemofiltration Too High or Too Low
  ICAAC 2016, June 16-20, 2016, Boston
Mark Mascolini
During continuous veno-venous hemofiltration (CVVH) for renal failure, more than half of nucleoside reverse transcriptase inhibitor (NRTI) doses were too high or too low, according to an analysis of 27 NRTI doses prescribed at a large academic medical center [1]. More than three quarters of the regimens included tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) or lamivudine (3TC).
As rates of kidney complications with HIV infection increase, more HIV-positive people may need CVVH, which removes fluid and solutes by convection via an extracorporeal blood pump. Like hemodialysis, CVVH can affect concentrations of NRTIs and may require dose adjustments. Researchers at Chicago's Northwestern Memorial Hospital conducted this study to determine proportions of appropriate and inappropriate NRTI doses in HIV patients during CVVH.
The study focused on HIV-positive adults taking an NRTI during CVVH sometime between September 2010 and September 2013 at Northwestern Memorial Hospital. The researchers retrospectively collected pertinent data from medical records. They created a peer-reviewed dosing table based on pharmacokinetic calculations of supplemental NRTI dosing needed during CVVH [2].
The analysis involved 12 patients taking a total of 27 NRTIs (10 TDF, 7 3TC, 6 FTC, 2 abacavir, and 2 zidovudine). Median age stood at 51 years (interquartile range [IQR] 45 to 52), 11 participants were men, 5 Caucasian, 4 African American, and 2 Hispanic. Median weight measured 84 kg (IQR 67 to 94), median viral load 44 copies, and median CD4 count 173.5. Reasons for CVVH were oliguria in 6 people, kidney failure in 4, and kidney injury in 2. Specific indications for CVVH were fluid removal/edema in 7, hemodynamic instability in 4, and lithium toxicity in 1. Median length of CVVH measured 6 days (IQR 3 to 9.25) and median hospital stay 27 days (IQR 19 to 31).
Ten of 12 study participants (83%) had at least one NRTI dose adjustment during CVVH. The researchers figured that 11 of the 27 NRTIs (41%) were dosed correctly, while doses of 9 NRTIs (33%) were too high and doses of 7 (26%) too low. Thus 59% of doses missed the mark.
The Northwestern team concluded that a high proportion of NRTI doses in these 12 HIV patients during CVVH "were not likely appropriate based on pharmacokinetic mathematical calculations." They called for further studies with pharmacokinetic sampling "to clarify appropriate dosing of NRTIs during CVVH."
1. McLaughlin MM, Masic I, Gerzenshtein L, et al. Appropriateness of NRTI dosing during CVVH at a large academic, medical center. ICAAC 2016, June 16-20, 2016, Boston. Abstract Sunday-417.
2. McLaughlin MM, Ammar AT, Gerzenshtein L, Scarsi KK. Dosing nucleoside reverse transcriptase inhibitors in adults receiving continuous veno-venous hemofiltration. Clin Drug Investig. 2015;35:275-80. http://link.springer.com/article/10.1007%2Fs40261-015-0275-9