ABSTRACT
This chapter considers the advantages and limitations of single drug therapy and multiple drug regimens. The optimal timing of medication intake reflects both pharmacokinetic and toxic parameters. In general, multiple daily doses are important for drugs with short half-lives and/or gastrointestinal toxicity. Pharmacokinetically, the optional spacing of antiepileptic drug administration throughout the day can be scientifically determined. Most idiosyncratic adverse effects occur within the first few months of therapy; some are severe and most require complete cessation of the medication. The single most important reason for maintaining patients on fewer medications is the difficulty of dealing with dose-related adverse effects. The patient is more likely, when on multiple medications, to have such effects for two reasons. First, the control of reasonable, nontoxic levels by the physician is clearly mote difficult with multiple drugs than with single medications and second, some dose-related adverse effects are additive.
