F_HD: An Index to Evaluate Drug Elimination by Hemodialysis

Abstract

Background: In hemodialyzed patients, physicians have to (1) adjust drug dosage for a creatinine clearance lower than 10–15 ml/min and (2) know whether or not the drug will be removed by the dialysis session to decide whether it may be administered before or after the session on dialysis days. However, of several indices being used to evaluate drug removal by dialysis none is appropriate and we suggest a novel index named F_HD, which reflects the role of hemodialysis clearance of a drug in its overall clearance during the session. Methods: Pharmacokinetic simulations were performed to test the influence of dialysis on the pharmacokinetics of some drugs, whether F_HD was considered or not, to determine when to administer the drug. F_HD was then calculated for several drugs and its value compared with other indices. Five hemodialysis patients from our department for whom the time of drug administration was determined according to F_HD were included in a small study and their drugs’ trough concentrations were monitored. Results: F_HD emphasized that considering hemodialysis clearance alone may lead to false interpretations of the potential dialyzability of some drugs. In our patients, who received their treatment according to the ‘F_HD rule’, monitoring of trough levels gave satisfactory results. Conclusion: The use of the ‘F_HD rule’ should be tested on a long-term administration basis to confirm our conclusion. F_HDcould be the index of choice to determine when to administer a drug, before or after the session, in hemodialysis patients.

Management of patients with end-stage renal disease undergoing chemotherapy: recommendations of the Associazione Italiana di Oncologia Medica (AIOM) and the Società Italiana di Nefrologia (SIN)

“…The third parameter, named F HD , was proposed by Launey-Vacher et al in 2005. 17 It was derived from a formula that took into account the amount of drug effectively removed by dialysis, but its relationship to the amount eliminated through the process of extrarenal removal, still active in dialysis patients. F HD represents the contribution of dialysis to the overall elimination of a substance.…”

When ESKD complicates cancer screening and cancer treatment

“…Unfortunately, there is little information on the dosing of most chemotherapeutic agents in dialysis patients being treated for cancer. Launey‐Vacher introduced a novel parameter he termed F HD , which represents the contribution of dialysis to the overall elimination of a substance, as determined by measuring drug concentrations in spent dialysate 53 . The F HD is widely accepted and used in practice.…”

“…If the F HD of a drug is <25%, the HD clearance is considered insignificant compared with the total body clearance, so a dose adjustment is not needed, and the drug can be given before or after dialysis 53 . When the F HD exceeds 25% the dose should be adjusted and the drug should be administered after the dialysis treatment 53 . Table 4 groups medications used to treat cancers by their class and summarizes recommendations for dosage adjustment in dialysis patients.…”

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“…Si celui-ci est supérieur à 25 %, le médicament doit être considéré comme dialysable et doit donc être administré après la séance, les jours d'hémodialyse [8].…”