ABSTRACT
BackgroundSince its introduction in modern medicine, naturalistic observations emerged about possible uses of lithium treatment for conditions different from recurring affective disorders, for which it is still a first-line treatment option. Some evidence about the antiviral properties of lithium began in the early 1970s, when some reports found a reduction of labial-herpetic recurrences. The present review aims to present most of the pre-clinical and clinical evidence about lithium's ability to inhibit DNA and RNA viruses, including Coronaviridae, as well as the possible pathways and mechanisms involved in such antiviral activity.Main bodyDespite a broad number of in vitro studies, the rationale for the antiviral activity of lithium failed to translate into methodologically sound clinical studies demonstrating its antiviral efficacy. In addition, the tolerability of lithium as an antiviral agent should be addressed. In fact, treatment with lithium requires continuous monitoring of its serum levels in order to prevent acute toxicity and long-term side effects, most notably affecting the kidney and thyroid. Yet lithium reaches heterogeneous but bioequivalent concentrations in different tissues, and the anatomical compartment of the viral infection might underpin a different, lower need for tolerability concerns which need to be addressed.ConclusionsLithium presents a clear antiviral activity demonstrated at preclinical level, but that remains to be confirmed in clinical settings. In addition, the pleiotropic mechanisms of action of lithium may provide an insight for its possible use as antiviral agent targeting specific pathways.
ABSTRACT
Currently, in psychiatry, lithium is a drug of choice as a mood stabilizer in the maintenance treatment of bipolar disorder for the prevention of manic and depressive recurrences. The second most important psychiatric use of lithium is probably increasing the efficacy of antidepressants in treatment-resistant depression. In addition to its mood-stabilizing properties, lithium exerts antisuicidal, antiviral, immunomodulatory, and neuroprotective effects. The goal of the review is to describe the experimental and clinical studies on the last three properties of lithium. Antiviral effects of lithium pertain mostly to DNA viruses, especially herpes viruses. The therapeutic effects of lithium in systemic and topical administration on labial and genital herpes were demonstrated in clinical studies. There is also some evidence, mostly in experimental studies, that lithium possesses antiviral activity against RNA viruses, including coronaviruses. The immunomodulatory effect of lithium can mitigate "low-grade inflammatory" conditions in bipolar illness. The neuroprotective properties of lithium make this ion a plausible candidate for the prevention and treatment of neurodegenerative disorders. A favorable effect of lithium was shown in experimental models of neurodegenerative disorders. On the clinical level, some preventive action against dementia and moderately therapeutic activity in Alzheimer's disease, and mild cognitive impairment were observed. Despite promising results of lithium obtained in animal models of Huntington's disease and amyotrophic lateral sclerosis, they have not been confirmed in clinical studies. A suggestion for common mechanisms of antiviral, immunomodulatory, and neuroprotective effects of lithium is advanced.