The Significance of Deviation in Time From the 12-hour Standard Serum-clozapine Monitoring.

The role of Therapeutic Drug Monitoring (TDM) in clozapine dose adjustment have been debated. Blood samples for s-clozapine monitoring should be drawn 12 hours post dose. The scope of this trial is to describe changes of s-clozapine and s-N-desmethyl-clozapine within the range of 10-14 hours after the last administration of clozapine .

Several factors can influence s-clozapine and thereby the occurence of dose-related adverse reactions and level of treatment response. The role of Therapeutic Drug Monitoring (TDM) in clozapine dose adjustment have been debated. Blood samples for s-clozapine monitoring are recommended to be drawn 12 hours post dose. Uncertainty regarding the timing of blood sampling and the individual pharmakokinetics for clozapine +/- 2 hours from the 12-hour timepoint, leads to uncertainty regarding the comparability of serum concentrations and the information hold within them. The scope of this trial is to describe changes of s-clozapine and s-N-desmethyl-clozapine within the range of 10-14 hours after the last administration of clozapine . In addition we want to investigate if any of the following covariates might affect the change of s-clozapine and s-N-desmethyl-clozapine: Sex, age, BMI, co-medications, signs of infection, caffeine intake and smoking.