Abstract Background: Lithium is often used in bipolar disorder and occasionally in unipolar depression. Non-steroidal anti-inflammatory drugs (NSAIDs) and diuretics are frequently prescribed and their interaction with lithium is based mainly in few small studies. Objectives: Conduct a review, identify different interaction patterns and discuss treatment options. Methods: Three searches were made in PubMed in January 2016: 1) using the keywords “lithium” [and] “non-steroidal anti-inflammatory”; 2) using the keywords “lithium” [and] “diuretics” and the filter “title/abstract”; 3) using the terms “lithium” [and] “toxicity” and the filters “title” [and] “review”. From the 293 remaining articles, 10 were selected. Another search in Scielo.org was made, using the term “lítio” and the filter “Psiquiatria”. Two articles were selected from the initial 53. Six textbooks were added to expand the evidence, achieving a total of 18 references. Results: The majority of NSAIDs and diuretics rises lithium levels, specially thiazides. However, some show great variability or no interaction at all, and others even decrease lithium levels. Discussion: Lower-doses, shorter durations, lithium adjustments and levels' follow-ups are recommended, especially in elderly and multiple co-morbid patients.