[Lithium]

Abstract

Lithium salts are used in psychiatry, for their sedative properties in states of agitation and, above all, for their ability to prevent recurring manic and depressive episodes in manic-depressive psychosis. In addition to manic-depressive psychosis, lithium is used as an antidepressant and the treatment of aggressive behaviors. Pharmacologic characteristics of lithium are incompletely elucidated; a few sedative and antiaggressive properties have been demonstrated in animals, but lithium fits into none of the known classes of psychoactive agents. Following absorption into the body, lithium does not bind to proteins. Penetration through the blood-brain barrier is poor. Elimination is mainly through the kidneys. Penetration of lithium into cells seems to vary across individuals. Lithium has a number of neurochemical effects, including stabilization of the number and sensitivity of monoaminergic receptors, which may be the mechanism for the drug's therapeutic properties. The main rule of lithium treatment is to achieve serum levels between 0.6 and 1 nM/l. Before starting a patient on lithium, tests are needed, especially to assess renal function: patients with renal failure are at risk for accumulation of lithium with toxic side effects. Most of the side effects are minor. The only serious risk is hyperlithemic intoxication that may cause mental confusion, coma and death. Lithium may induce malformations if given during the first trimester of pregnancy. The only true contraindications to lithium are renal failure, treatment by thiazide diuretics, and organic brain disease.