Indications: prophylaxis in manic-depressive illness & recurrent depression, treatment of mania; aggressive or self-mutilating behavior. Lithium is unsuitable for children.

Special precautions: Lithium salts have a narrow therapeutic/toxic ratio and should therefore not be prescribed unless facilities for monitoring serum-lithium concentrations are available. Doses are adjusted to achieve serum-lithium concentration of 0.4–1 mmol/litre (lower end of the range for maintenance therapy and in elderly patients) on samples taken 12 hours after the preceding dose. It is important to determine the optimum range for each individual patient.

Overdosage: usually with serum-lithium concentration of over 1.5 mmol/litre, may be fatal and toxic effects include tremor, ataxia, dysarthria, nystagmus, renal impairment, and convulsions. If these potentially hazardous signs occur, treatment should be stopped, serum-lithium concentrations redetermined, and steps taken to reverse lithium toxicity. In mild cases withdrawal of lithium and administration of generous amounts of sodium salts and fluid will reverse the toxicity. Serum-lithium concentration in excess of 2 mmol/litre require urgent treatment as Emergency Treatment of Poisoning. hyperreflexia and hyperextension of limbs, convulsions, toxic psychoses, syncope, renal failure, circulatory failure, coma, and occasionally, death;

Cautions: measure serum-lithium concentration regularly (every 3 months on stabilised regimens), measure renal function and thyroid function every 6–12 months on stabilised regimens and advise patient to seek attention if symptoms of hypothyroidism develop (women at greater risk) e.g. lethargy, feeling cold; maintain adequate sodium and fluid intake; test renal function before initiating and if evidence of toxicity, avoid in renal impairment, cardiac disease, and conditions with sodium imbalance such as Addison's disease; reduce dose or discontinue in diarrhoea, vomiting and intercurrent infection (especially if sweating profusely); psoriasis (risk of exacerbation); pregnancy, breast-feeding, elderly (reduce dose), diuretic treatment, myasthenia gravis; surgery; avoid abrupt withdrawal.

Note: Patients should maintain adequate fluid intake and avoid dietary changes which reduce or increase sodium intake.

Withdrawal of treatment: While there is no clear evidence of withdrawal or rebound psychosis, abrupt discontinuation of lithium increases the risk of relapse. If lithium is to be discontinued, the dose should be reduced gradually over a period of a few weeks and patients should be warned of possible relapse if it is discontinued abruptly.

Interactions: Irreversible toxic encephalopathy may occur when lithium is given concurrently with high doses of haloperidol, fluphenazine, or flupentixol.

Side Effects: gastro-intestinal disturbances, fine tremor, renal impairment (particularly impaired urinary concentration and polyuria), polydipsia, leucocytosis; weight gain and oedema (may respond to dose reduction); hyperparathyroidism and hypercalcaemia; signs of intoxication are blurred vision, increasing gastro- intestinal disturbances (anorexia, vomiting, diarrhoea), muscle weakness, increased CNS disturbances (mild drowsiness and sluggishness increasing to giddiness with ataxia, coarse tremor, lack of co-ordination, dysarthria), and require withdrawal of treatment; goitre, raised antidiuretic hormone concentration, hypothyroidism, hypokalaemia, ECG changes, and kidney changes may also occur.

Dose: treatment, Initially 1.5-2 g daily, adjusted to reach plasma concentration of 0.4-1.0 m mole of Li/liter by tests on samples taken hours after the preceding dose on the fourth to seventh day of treatment, then weekly until dosage has remained constant for 4 weeks and every 3 months thereafter.

Prophylaxis, initially, 0.5-1.2 g daily.

Daily doses are usually divided and sustained release preparations normally given twice daily.