Lithium is effective in treatment of: Acute mania prophylaxis of manic depression

Lithium:

The mechanism of action is not fully understand but possible mechanism are: it alter Na ion transport across cell membrane in nerve and muscle

cell (decrese sodium release) it alter metabolism of catecholamine and serotonin it inhibit inositol monophophatase. it decrease dopamine release.

Mechanism of action:

It given orally as carbonate salt 2- 3 times daily during meal often higher dose in evening . the sustained release tablet is given once in the evening.

half life is 18-30 hourz. And it does not bind with plasma protein. How log it works 1-3 weeks It has narrow therapeutic index. That’s why monitoring of plasma

concentration is necesoory and it is done by salivery lithium concentration

Pharmacokinetics:

Renal function thyroid function ECG

It has narrow therapeutic index so plasma concentration monitoring is essential during treatment

1-4 days 2 weeks 7 weeks 3months

LITIUM PRETREATMENT

TESE:

Lithium monitoring:

Lithium is available in following dosage forms:

Dosage form of lithium:

Dosage form StrengthTablet 300mgSustain release tablet 400mgCapsule 300mgliquid 8mEq/ mL

In acute cases 1800mg per day in divided doses. mantaince dose is 900mg-1200mg per day In case of liquid preparation: 10mL 3times per day

Dose:

For prophylaxis: minimum effective level 0.4mmol/L Optimum range 0. to 0.7 mmol/L For acute mania 0.8 to 1.0mmol/L

Minimum plasma level:

Lithium is unevenly distributed through out the body it follows two compartment model.

Lithium is mainly excreted by kidney . lithium clearance is 20 percent of creatinine clearance.

Distribution:

Excretion:

Due to narrow therapeutic range lithium is not prescribed unless facilitates for serum lithium concentration during treatment.lithium excretion is first order reaction.

Blood sample should be drawn for 12 hours after the evening dose. Blood level report is measured in SI units.so 100mg of lithium carbonate is equivalent to 2.7mmol of lithium ion. 100mg of lithium citrate is equivalent to 1.1mmol of lithium ion.

Practical implementation:

Contraindication:

Renal and cardiovascular disease. Dehydration Pregnancy Lactation Patient on diuresis

>1.4mmol/L Early toxic effect: GIT effects CNS effects >2mmol/L Serious toxic effect: disorientation Seizures coma death

Lithium toxicity:

Lithium management for toxicity:

Stop lithium immediately increase fluid intake stimulate diuresis >3mmol/L then heamodialysis is essential.