| Popis: |
The amount of drug clearance during online hemodiafiltration (HDF) is determined by (1) the pharmacokinetic properties of a drug defined by its absorption, distribution, metabolism and elimination (ADME) characteristics, (2) dialysis characteristics, including membrane properties, treatment time and blood-, dialysate- and ultrafiltration flow rates, and (3) patient factors. For several drugs, especially those within the middle molecular weight range, with low protein binding and neutrally or positively charged, clearance may be substantially higher during HDF as compared to conventional low flux hemodialysis. Based on drug characteristics, the expected additional effect of a high ultrafiltration rate, as indicated by a high convection volume, can be estimated. This is shown for anticoagulants, antibiotics and antiviral drugs. For drugs with an expected additional effect of convection and for drugs with a narrow therapeutic window, therapeutic drug monitoring may be advisable. Comparative data from clinical studies is scarce. Hence, for an individual patient it may be relevant to calculate the total amount of a drug excreted during an HDF session. This can easily be performed in routine clinical practice and may guide the clinician to estimate the dose of the drug needed for suppletion upon completion of HDF treatment. Examples are provided how to calculate drug suppletion after HDF. Collectively, this chapter is intended as a guidance to optimize pharmacotherapy in online HDF patients. |
