Lithium therapeutic dose monitoring in human saliva.

BACKGROUND Lithium carbonate is valuable and effective agent in the treatment and prophylaxis of mood disorders, particularly bipolar disorder (BD). Due to its narrow therapeutic range, frequent serum lithium estimation is necessary. To avoid the discomfort of frequent venipuncture, a non-invasive method for serum lithium concentration is needed. An alternative method of determining lithium level could be saliva or urine. Literature data regarding the reliability of saliva lithium levels is not conclusive. MATERIAL AND METHODS The aim of this study is to provide an overview of possibility to replace blood serum with saliva look through research in that field. RESULTS Some authors conclude that there is constant ratio between serum and saliva lithium level and they suggest that saliva can replace serum for estimation lithium level. Other revealed that saliva/serum lithium ratio is constant individually, so saliva/serum lithium ratio should be estimated individually. Finally there are studies excluding the possibility of replacement serum with saliva. CONCLUSIONS There is little number of studies on saliva clinical use in lithium level monitoring. Further studies should base on current data including methods of obtaining saliva and its biochemical analysis, collecting samples in a specific time frame from the last dosage of lithium, as well as inter-subject or intra-subject measurements.