Individualization of lithium therapy based on the monitoring of its level in saliva.

Purpose: Bipolar disorder (BD) is a mental disorder that affects approximately 2-3% of the population. The mainstay of treatment in bipolar disorder is lithium, which has also found an important application in the potentiation of antidepressants in drug-resistant depression, in the course of both bipolar disorder and recurrent depressive disorders.

Views: The narrow therapeutic range of lithium and the frequent side effects it causes necessitates the monitoring of its concentration in the blood, which requires the periodic presence of the patient in a clinical laboratory. This is costly and inconvenient for patients, and is a common obstacle for psychiatrists who are reluctant to prescribe this effective drug precisely because of the inconvenience of having to monitor blood levels. If regular monitoring of lithium levels could be carried out without the need to puncture the vein and visit a clinic it would save time for both patients and healthcare professionals, avoid discomfort, and make difficult-to-reach patients easier to manage.

Conclusions: Saliva in the monitoring of the lithium level is a promising biological material and offers the possibility to quickly estimate the individual lithium dosage for a specific patient which will provide the required therapeutic level. Saliva can be collected at home without the involvement of qualified personnel. Providing a more convenient and effective means of monitoring lithium therapy (e.g. the proposed non-invasive saliva level test) would enable safer, more effective therapy (more likely to maintain therapeutic blood levels) and an individualized therapeutic approach to a patient.