Therapeutic drug monitoring and pharmacokinetic dose prediction methods.

Therapeutic drug monitoring is recommended in suspected drug overdosage, in cases of therapeutic failure, in the establishment of regimens in patients with altered pharmacokinetics and in patients with unknown previous medications. Pharmacokinetic dose prediction methods have been developed allowing individual dosage adaptation. As examples, the three-point method of Sawchuk and the Bayesian technique are described. Drug concentrations could be predicted with sufficient accuracy by use of the three-point method in critically ill patients treated with aminoglycosides or flucytosine. Bayesian forecasting proved to be useful in predicting the nocturnal concentration curves in patients with asthma treated with a sustained-release preparation of theophylline for once-daily dosage. The efficiency of drug treatment can be considerably improved by monitoring serum drug concentrations and individualizing dosage using pharmacokinetic methods.