[Dose-effect relation in therapy of cytostatic-induced leukopenia with lithium carbonate]

Lithium is used increasingly for attenuation of chemotherapy induced leukopenia in infants and adolescents. Thus, pharmacological data are needed. The purpose of this study was to give recommendations for oral dosage yielding efficient serum levels. Furthermore, two methods of serum level determination were compared. Flame emission photometry using microsamples gave results comparable to atomic absorption photometry. The correlation of oral dose and serum level was investigated in a phase I study. A wide range of serum levels related to an identical oral dose was found. Therefore, frequent serum level determinations are needed to realize efficacy and to avoid toxicity. The correlation between increasing serum levels and leucocyte count was investigated in the first part of a phase II study. No significance was found; i.e. a linear progressing dose-effect relation does not exist. The time course of leukocyte count was analysed for two different serum level groups in the second part of the phase II study. A significant correlation was found in the group with a serum level greater 0,7 mmol/l.