Lithium Carbonate

Question 1

How does it cause its antimanic effects?

Answer 1

-Blocks the IP3, DAG pathway

Question 2

How does it cause its side effects?

Answer 2

1. replaces Na+ in the excitable tissue.
2. Blocks Adenylyl Cyclase.
3. Discouples Receptor from its G protein.

Question 3

pharmacokinetics &general facts

Answer 3

-Well absorbed
-Lithium accumulates in neuronal tissues and kidney so 1-2 weeks needed to establish the therapeutic Serum level.
-Elimination: Lithium is actively reabsorbed
if there is lack of sodium in the body, then higher amount of Lithium is reabsorbed and thus its toxicity is increased.
(competition with sodium)
-Lack of sodium in the body can be because of: exerice, diuretics or diarrhea.
-Has a narrow therapeutic range so a small dose causes toxicity (must monitor the Se level of the pts.)
-not metabolised
-eliminated unchanged in urine (24hr)
-doesn’t bind to serum proteins

Question 4

Side effects of Lithium Carbonate at normal dose

Answer 4

1. Tremor, sedation, nausea, vomiting
2. Hypothyroidism: doesn’t let TRH cause an effect because it discouples the proteins.
3. Interstitial nephritis (accumulates in the kidney)
4. Nephrogenic diabetis insipidous ( decreases the effect of ADH–> treat by thiazide diuretics eg hydrochlorothiazide)
5. teratogenic ( not used in pregnancy)

Question 5

Side effects of Lithium Carbonate at toxic doses

Answer 5

1. hyperactivity

2. seizures & comma

Question 6

Dosing for Lithium Carbonate

Answer 6

long term profilactic: 0,6-1 mmol/L

acute mania: 1-1,2 mmol/L

toxic dose: 1,5-1,7 mmol/L

Question 7

Indications for Lithium Carbonate

Answer 7

1. Golden standard for Mania
   both in depressive and manic phases to avoid the switch between them-not effective in acute mania

2.unipolar depression
enhances the effect of antidepressants. (mood stabilizer actually not antimanic drug)