Drug-induced encephalopathy secondary to non renal dosing of common medications in Two dialysis patients.

: The U.S. end-stage renal disease (ESRD) population continues to increase. Adjustment of several drugs administered to dialysis patients is mandatory because of decreased--and sometimes totally absent--renal clearances. Gabapentin, a newer anticonvulsant increasingly used for several other clinical indications, is excreted in the urine unchanged. Its half-life of 5 - 9 hours is increased to up to 132 hours in anuric patients. Excretion of acyclovir an antiviral agent, occurs predominantly through the kidney (glomerular filtration and tubular secretion). Its normal plasma half-life is 2 - 3 hours; dosage modifications are obligatory in renal insufficiency. In 2008, we encountered 2 ESRD patients on dialysis who exhibited significant neurotoxicity with encephalopathy after gabapentin and acyclovir were given at the usual adult doses. Following prompt drug discontinuation and continued daily hemodialysis or peritoneal dialysis respectively, both patients were discharged home, in normal clinical condition, after 3 days. With the increasing ESRD (and CKD) populations, health care providers other than nephrologists will have increasing contact with these patients. Those providers must consider drug dose modifications according to residual renal function. Algorithms for appropriate renal drug dosing are available from various sources. Pragmatic tactics of this kind will avoid significant morbidity and mortality. In addition, this approach will save millions of now increasingly scarce health care dollars.