Thesis (M.Sc. in Pharm.)--Chulalongkorn University, 1996

To apply pharmacokinetic theory to adjust dosage regimen of lithium for individual patients by taking his/her blood lithium level along with his/her clinical response both in efficacy and adverse effects or toxicity into consideration and to evaluate whether or not the dosage regimens of lithium currently prescribed would resulted in blood lithium levels which were within the therapeutic range. Of the 42 patients inclulded in this study, the blood lithium levels of 80.95% of patients were within the therapeutic range while 11.91% were in the subtherapeutic level and 7.14% were in the overtherapeutic level. Dosage regimens had been adjusted in six patients whose clinical responses were unsatisfactory. The doses were increased in four patients which resulted in much better clinical efficacy while lithium were discontinued in two patients since lithium toxicity had observed. There was significant difference, p<0.05, between measured lithium level and predicted lithium level using the pharmacokinetic parameters which obtained from patients' general data and his/her serum creatinine. Measured lithium levels were related to clinical responses both in efficacy and adverse effects or toxicity. Blood lithium levels predicted from lithium clearances were more accurate than those predicted from serum creatinine. The results from this study suggest that lithium therapeutic level monitoring could help enhancing better efficacy and safety in lithium therapy.