Psychopharmacology in patients with renal failure.

The prescription of medications for a patient with kidney failure requires special consideration since the kidneys are major organs of excretion and regulator the body's fluid environment. Physicians need to have a working knowledge of the pharmacokinetics of the medications they intend to prescribe. Protein binding of medications is a central factor, especially in end-stage kidney disease where its impairment is associated with higher available drug levels. Fortunately, almost all psychotropics are fat soluble, are excreted by the liver and are not dialyzable. Lithium is an exception, but it may be used because it is totally excreted by the kidneys and its dialyzability enables single dosing after dialysis runs. Some benzodiazepines such as diazepam have active metabolites and their use should be avoided. The general rule is that no more than two-thirds of the maximum dose for a patient with normal renal function should be the maximum dose for a hemodialysis patient and that drug levels should be performed at least monthly and immediately after initial dosing.