Lithium (Mania)

Question 1

What is Lithium used for?

Answer 1

For tx of the mania aspect of Bipolar disorder.

Question 2

What is the basic MOA of Lithium?

Answer 2

Inhibition of the enzyme Inositol Monophosphate which results in no production of inositol. No Inositol means no PIP2 recycling , which wont convert to PLC which wont convert to DAG, which means no increased intracellular Ca and thus blockade of the secondary messenger effects of calcium.

Question 3

What is the effect of using Lithium?

Answer 3

Inhibition of the signaling in response to serotonin and NE, thus modulating energy metabolism, neuroprotections and increased neuroplasticity.

Question 4

What is the Tx use of lithium?

Answer 4

Tx of acute mania and prevention of recurrance, decreases suicide rate and can be used with anti psychotics.

Question 5

Can Lithium be used in a patient having acute bouts of mania?

Answer 5

No it takes days to weeks to kick in, we need to use other drugs in the mean time.

Question 6

What are the AE’s of lithium?

Answer 6

Headache, weight gain, sedation, decreased libido, GI and derm side effects. Polyuria and polydipsia, NEPHROGENIC DIABITIS INSIPIDIS. Subclinical hypothyroidism. ECG changes and leukocutosis.

Question 7

What is the PK of Lithium in terms of distribution excretion and half life?

Answer 7

Distributed to wherever water can go, it has complete absorption. It is freely filtered in the glomerulus and 80% of it is reabosrbed. About 20 hr half life.

Question 8

What are signs of mild Lithium tox and what is the hallmark of Lithium use?

Answer 8

n/v/d, abdominal pain, sedation. Hallmark is FINE TREMOR.

Question 9

What are the signs of acute toxicity of lithium?

Answer 9

Vomitting, profuse diarrhea, GROSS TREMOR, slurred speech, hyperreflexia, ataxia, coma, convulsions and death.

Question 10

How would we tx lithium tox?

Answer 10

Supportive care, removal of the Li ion via dialysis.

Question 11

Preggo and Lithium use?

Answer 11

Category D, need to adjust for high volume of distribution if mother is at risk and needs lithium. However must account for less Vd when baby is born. Secreted in breast milk and crosses the placenta.

Question 12

If mother is taking Li, what can the baby present with?

Answer 12

Hypotonia (floppy baby syndrome), cardiac murmur (Ebstein anomaly).