Current Medicinal Chemistry             1875-533X/20 $65.00+.00 © 2020 Bentham Science Publishers Branislava Medić 1,* , Marko Stojanović 1 , Bojan V. Stimec 2 , Nevena Divac 1 , Katarina Savić Vujović 1 , Radan Stojanović 1 , Mirjana Čolović 3 , Danijela Krstić 4 and Milica Prostran 1 1 Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia; 2 Anatomy Sector, Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland; 3 Department of Physical Chemistry, “Vinča“ Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia; 4 Institute of Medical Chemistry, Faculty of Medicine, University of Belgrade, Belgrade, Serbia A R T I C L E H I S T O R Y Received: March 02, 2018 Revised: July 16, 2018 Accepted: July 19, 2018 DOI: 10.2174/0929867325666180904124733 Abstract: Lithium is the smallest monovalent cation with many different biological effects. Although lithium is present in the pharmacotherapy of psychiatric illnesses for decades, its precise mechanism of action is still not clarified. Today lithium represents first-line therapy for bipolar disorders (because it possesses both antimanic and antidepressant properties) and the adjunctive treatment for major depression (due to its antisuicidal effects). Beside, lithium showed some protective effects in neurological diseases including acute neural injury, chronic degenerative conditions, Alzheimer's disease as well as in treating leucopenia, hepatitis and some renal diseases. Recent evidence suggested that lithium also possesses some anticancer properties due to its inhibition of Glycogen Synthase Kinase 3 beta (GSK 3 β) which is in- cluded in the regulation of a lot of important cellular processes such as: glycogen metabolism, inflammation, immunomodulation, apoptosis, tissue injury, regeneration etc. Although recent evidence suggested a potential utility of lithium in different conditions, its broader use in clinical practice still trails. The reason for this is a narrow therapeutic index of lithium, numerous toxic effects in various organ systems and some clinically relevant interac- tions with other drugs. Additionally, it is necessary to perform more preclinical as well as clinical studies in order to a precise therapeutic range of lithium, as well as its detailed mechanism of action. The aim of this review is to summarize the current knowledge concern- ing the pharmacological and toxicological effects of lithium. Keywords: Lithium, pharmacological effects, mechanism of action of lithium, mechanism of action of lithium in the brain, lithium in preclinical and clinical studies, adverse effects of lithium, drug interactions with lithium. 1. INTRODUCTION Lithium is the smallest monovalent cation with a lot of different biological effects. Although recent experi- mental animal studies showed that lithium represents an essential nutrient, there is still no consensus regard- ing optimum lithium concentration. On the other hand, *Address correspondence to this author at the Department of Phar- macology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia; Tel: 381-11-3643-384; Fax: + 381-11-3643-397; E-mail: brankicamedic@gmail.com an increase in the level of lithium over 1.2 mM in the blood causes acute toxicity (nausea, diarrhea, trembling etc.), and the death may occur above 2 mM. The lack of therapeutic range of lithium could be explained by the still unknown mechanisms of action and the lack of lithium specific targets. Clinical use of lithium has been limited due to its narrow therapeutic index and toxic effects in various organ systems. However, lith- ium has been used in clinical practice for decades [1-4]. The digestive absorption of lithium is complete and the maximum plasma concentration is observed two to Send Orders for Reprints to reprints@benthamscience.net Current Medicinal Chemistry, 2020, 27, 337-351 337 REVIEW ARTICLE Lithium - Pharmacological and Toxicological Aspects: The Current State of the Art