Lithium

Sample for Lithium

1. It is done on the serum of the patient.
2. The time to take the sample is 12 hours after the dose.

Indications for Lithium

1. It is used particularly in psychiatric patients on lithium therapy :
   1. Mania.
   2. Manic depressive illness (Bipolar affective disorder).
   3. The manic phase of the affective disorder.
   4. For the treatment and prevention of mania and people with bipolar disorders.

Definition of Lithium

1. Lithium, known as Eskalith, or Lithane, Lithonate as lithonate carbonate, is given for treating the manic phase of mania, affective disorder, and manic depressive disease.
2. This is present in the ultra-trace amount.
3. Lithium is an element like sodium and potassium.
4. Its salt may be found on earth in small quantities.
5. The amount of river water and the well is very low.
6. In plants and animals, the tissue is also low for lithium.

Mechanism of action of lithium

1. It is postulated that lithium helps in the reuptake of catecholamines, decreasing their concentration in the neuronal junction.
2. This reduction of catecholamines at the neuronal junction produces a sedation effect on the central nervous system.
3. Lithium also regulates the distribution of sodium, calcium, and magnesium in the nerve cells, reducing glucose metabolism that affects nerve function.
4. Also, regulate the glucose metabolism that affects nerve function.
5. The kidneys do the clearance. So in the case of renal damage, the clearance is delayed.

Absorption of Lithium

1. There is the complete absorption of lithium from the GI tract.
2. The peak level reaches within 2 to 4 hours after the intake of the drug.
3. This is free in the blood and does not bind to the protein.
4. The clearance in the blood is biphasic.
5. First phase:
   1. 30% to 40% cleared with a half-life of 22 hours.
6. Second phase:
   1. The remainder of lithium present in the ion pool is cleared with a half-life of 48 to 72 hours.
7. The clearance is mainly dependent upon the renal function where active absorption occurs.
8. Lithium passes through the glomerular membrane and is reabsorbed in the proximal convoluted tubules.
   1. In case of dehydration, fever, watery stool, vomiting, and hot weather intoxication of lithium, chances increased.
   2. In the case of dehydration, the proximal tubular response to the reabsorption of sodium and lithium is the reduction of clearance.
9. The decreased renal function causes prolonged clearance time.

9. Lithium carbonate is used as a drug to treat patients with bipolar manic depression.
   1.   When given to patients then regulates the neurotransmission in the brain.

Therapeutic dose of lithium:

1. The lithium level should be monitored very carefully because the Level for the therapeutic and toxic doses is very narrow.
   1. Therapeutic level =  0.8 to 1.2 meq/L (meq/L = mmol/L).
   2. Maintenance dose = 0.5 to 1.2 mmol/L.
   3. Toxic level = >2.0 meq/L

2. The standardized  12-hours postdose serum lithium concentration should be assessed as an adequate dose.
   2. The optimum level needs to be 1.0 to 1.2 mmol/L therapeutic dose.
   3. The concentration of lithium 1.2 to 1.5 mmol/L is the warning range.
   4. The lithium level >1.5 mmol/L in a 12-hours post-dose suggests a risk of intoxication.
3. There is a lab variation of these values from lab to lab.
4. Decreased dietary sodium leads to a decrease in the excretion of lithium.

The toxic dose of lithium:

1. Lithium concentration of >2.5 mmol/L indicates severily intoxication by:
   1. Muscle rigidity.
   2. Hyperactive deep tendon reflex.
   3. Epileptic seizures.

Stop the Lithium when the patient feels the following signs and symptoms:

1. The patient has dizziness, drowsiness, or a lack of energy.
2. There may be muscle weakness and ataxia.
3. The patient may have nausea, vomiting, or diarrhea.
4. Difficulty in speech.
5. There may be a lack of coordination.
6. The patient may be confused.
7. May get irregular tremors or shake.
8. There may be restlessness.
9. There may be myoclonic twitching.
10. There may be life-threatening seizures.
11. Blood excretion of lithium is parallel to sodium excretion. It passes

• The recommended time for the lithium estimation is 12 hours after the dose:

The normal value of Lithium

Source 2 

• Therapeutic level: 0.8 to 1.2 meq/L
• Toxic level :  > 2.0 meq/L
• (meq/L = mmol/L, both values are the same)

Source 4

• Acute mania = 0.6 to 1.2 meq/L
• Protection against future episodes in patients with bipolar disorder = 0.8 to 1.0 meq/L
• Toxic level = >2 meq/L

The side effects of the  raised level of lithium:

Treatment with Lithium

• Lithium is given to the patient as lithium carbonate.

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