Lithium salt
Lithium salts are chemical salts of
lithium used as
mood stabilizing drugs, primarily in the treatment of
bipolar disorder,
depression, and
mania; but also in treating
schizophrenia. Usually
lithium carbonate (Li
2CO
3), but sometimes the
citrate salt,
lithium citrate is used. The orotate salt,
lithium orotate, may also be used. The salt is widely distributed in the
central nervous system and interacts with a number of neurotransmitters and receptors, decreasing
noradrenaline release and increasing
serotonin synthesis.
The use of lithium salts was developed by the Australian psychiatrist
John Cade, after an accidental discovery of their effects on animals led to trials on human patients.
Treatment
\nLithium treatment is used to sedate overactive and euphoric patients. Initially, lithium is often used in conjunction with antipsychotic drugs as it can take up to a week for lithium to have an effect. Lithium treatment is generally considered to be unsuitable for children.
Lithium toxicity and side effects
\nThose who use lithium should receive regular blood tests and should monitor the thyroid and kidney for toxic damage. As it is a salt, lithium can cause dehydration. Dehydration, which is compounded by heat, can result in increasing lithium levels.
High doses of haloperidol, fluphenazine, or flupenthixol may be hazardous when used with lithium; irreversible toxic encephalopathy has been reported.
Lithium salts, with the exception of lithium orotate, have a narrow therapeutic/toxic ratio and should therefore not be\nprescribed unless facilities for monitoring plasma concentrations are\navailable. Patients should be carefully selected. Doses are adjusted to achieve\nplasma concentrations of 0.6 to 1.2mmol Li+/litre (lower end of the\nrange for maintenance therapy and elderly patients) on samples taken 12 hours\nafter the preceding dose. Overdosage. usually with plasma concentrations over\n1.5mmol Li+/litre, may be fatal and toxic effects include\ntremor, ataxia, dysarthria, nystagmus, renal impairment, and\nconvulsions. If these potentially hazardous signs occur, treatment should be\nstopped, plasma lithium concentrations redetermined, and steps taken to reverse lithium toxicity.
Lithium toxicity is compounded by sodium depletion. Concurrent use of\ndiuretics that inhibit the uptake of sodium by the distal tubule (e.g.\nthiazides) is hazardous and should be avoided. In mild cases withdrawal of\nlithium and administration of generous amounts of sodium and fluid will reverse\nthe toxicity. Plasma concentrations in excess of 2.5 mmol Li+/litre\nare usually associated with serious toxicity requiring emergency treatment.\nWhen toxic concentrations are reached there may be a delay of 1 or 2 days\nbefore maximum toxicity occurs.
In long-term use, therapeutic concentrations of lithium have been thought to\ncause histological and functional changes in the kidney. The significance of\nsuch changes is not clear but is of sufficient concern to discourage long-term\nuse of lithium unless it is definitely indicated. Patients should therefore be\nmaintained on lithium treatment after 3-5 years only if, on assessment, benefit\npersists. Conventional and sustained-release tablets are available but it\nshould be noted that different preparations vary widely in bioavailability\nand a change in the formulation used requires the same precautions as\ninitiation of treatment. There seem few if any reasons for preferring one or\nother of the simple salts of lithium; the carbonate has\nbeen the more widely used but the citrate is also available.
Lithium overdosing
\nSigns that lithium levels within the body are too high include: confusion, diarrhea, lethargy, severe tremors, and/or an upset stomach.
Lithium and culture
\nAs with many other drugs, songs have been written about its perceived effects, "Lithium Sunset" by Sting and "Lithium" by Nirvana among others.
The soft drink 7Up, originally named "Bib-Label Lithiated Lemon-Lime Soda", contained lithium citrate until it was reformulated in 1950.
Further reading
\n* McIntyre RS, Mancini DA, Parikh S, Kennedy SH. "Lithium revisited." Can J Psychiatry. 2001 May;46(4):322-7.\n* Bowden CL, Brugger AM, Swann AC, Calabrese JR, Janicak PG, Petty F, and others. Efficacy of divalproex vs lithium and placebo in the treatment of mania. JAMA 1994;271:918–24.
External links
\n* "Lithium revisited"\n* 7-UP and lithium
Category:Antipsychotics
