Monitoramento da adesão ao tratamento com lítio

BACKGROUND: Lithium has been used as the treatment of choice for bipolar disorder. It is efficient in reducing depressive and maniac episodes and has an anti-suicidal effect. However, the effectiveness of lithium is decreased by low compliance to treatment, influenced by patient's characteristics and the pharmacological properties of lithium. OBJECTIVE: To review some of the clinical pharmacological aspects of lithium and its importance for the therapeutic monitoring of lithium, through concentration measurements and through translated to Portuguese self-report scales of non-compliance to lithium treatment. METHOD: Relevant basic and clinical scientific literature available in English and in Portuguese were searched in PUBMED and SCIELO with the words "lithium", "monitoring", "compliance" OR "adherence". RESULTS: Lithium is a drug with very low therapeutic index and difficult individual pharmacokinetic properties, leading to the necessity of intensive therapeutic monitoring, through lithium measurements in serum and in red blood cells. The rates of compliance to lithium prescription by Brazilian bipolar patients who attend outpatient treatment are between 60 and 85%, being higher than those of patients not receiving psychoeducational programs (compliance around 46%). The non-compliant patients present lower knowledge about lithium and their disorder and more negative attitudes toward the use of medication, besides the fear of side-effects. CONCLUSION: Biological monitoring helps in treatment adherence, through the improvement of therapeutic individualization and lithium dose adjustments, besides being helpful in the detection of drugs interactions.