Salivary and blood levels of neuroleptics during outpatient maintenance treatment

Salivary and blood levels of chlorpromazine, haloperidol and fluphenazine were measured by radioreceptor assay in 45 outpatients. All the patients were on less than 300 mg chlorpromazine (or its equivalent), were taking only a single neuroleptic, and had reached pharmacokinetic equilibrium. No correlation was found between salivary levels and blood levels for any of the three neuroleptics measured. The saliva-blood ratio for haloperidol was 2.2:1 while for chlorpromazine and fluphenazine it was 0.4:1 and 0.7:1 respectively. Salivary levels were detectable in all cases in which blood levels were undetectable. This indicates that salivary neuroleptic levels are sometimes concentrated compared with blood levels. The lack of correlation between salivary and blood levels of neuroleptics is discouraging with regard to a potential clinical use of salivary neuroleptic levels.