LITHIUM
At present Lithium is the only drug of its kind to exert prophylactic effect in manic depressive psychosis (M.D.P.) and is being extensively used at centres where its serum levels can be measured. It is neither sedative nor euphorient, but on prolonged admin, it acts as a mood stabiliser in M.D.P. given to patients in acute mania it gradually suppresses the episode taking 1-2 weeks; continued treatment prevents cyclic mood changes. Markedly reduced sleep time in manic patients is normalized.Acute hypomania, mania, recurrent mania. Depression cyclic & recurring. Prophylaxis of MDP. Recurrent neuropsychiatric illness. ADH secretion syndrome.
Generally started at 600 mg/day and gradually increased to yield therapeutic plasma levels; 900-1800 mg per day.
Pregnancy. Foetal goiter and other congenital abnormalities, specially cardiac, can occur; the new born is often hypotonic. C.N.S. disorders, nursing mothers.
Monitor renal & thyroid functions. Maintain salt & fluid intake. Drug interaction occurs with phenytoin, carbamazepine, haloperidol, diazepam, methyldopa, tetracycline, diuretics. Paediatrics: Not recommended. Pregnancy: Not usually prescribed. Lactation: Drug passes into breast milk. Elderly: Reduced dose may be necessary.
Nausea, vomiting, mild diarrhoea initially. Thirst & polyuria. Fine tremors and rarely seizures. C.N.S. toxicity-coarse tremors, giddiness, ataxia, motor in-coordination, nystagmus, mental confusion, slurred speech, hyper reflexia.
Diuretics reduce lithium excretion, NSAIDs increases the serum lithium level, synergistic effect with pancuronium and suxamethonium. Antidepressants, antiepileptics, sumatriptan increases the risk of CNS toxicity.
