Many common anesthetic drugs may be affected by renal dysfunction due to changes in compartment volumes, electrolytes, pH (acidemia resulting in a higher percentage of nonionized drug), decreased serum protein concentration resulting in increased bioavailability of protein-bound drugs, and impaired biotransformation and rates of excretion (Table 4.5). Loading doses do not need to be altered significantly in CKD as the duration of action of drugs administered by bolus is determined by redistribution, not elimination. With repeated dosing or long-term infusion, the duration of action is dependent on elimination, and maintenance doses of drugs with significant renal excretion should be reduced.