Serum level monitoring and clinical pharmacokinetics of lithium.

Short-term antimanic therapy with lithium and relapse-repressive, so-called "prophylactic" long-term therapy with lithium, may present clinical problems which demand an understanding of two cardinal properties of this form of therapy--the need to individualise the dose and the recognition that successful therapy involves the use of near-toxic dosage. Therefore, treatment must be constantly supervised, not only by the physician but also primarily by the patient himself, especially to avoid the ever-present risk of intoxication. Results of 25 years' clinical experience and more recent knowledge of the clinical pharmacokinetics of the lithium ion have shown that a serum level standardised with regard to dosage schedule, a fixed interval between last intake and blood sampling, blood sampling at the same hour, and choice of tablet brand, must all be considered essential to adjust dosage and to correctly monitor treatment. Optimum use of the lithium ion as a psychotherapeutic drug and of the standardised 12 hour lithium serum concentration, presupposes that the pharmacokinetics of the lithium ion are well understood by the clinician.