Lithium Flashcards
Give 2 examples of lithium formulations
- Lithium citrate
- Lithium carbonate
Why is it important to keep the patient on the same lithium formulation throughout treatment?
Contain different concentrations of lithium
On what basis is lithium prescribed?
By brand
What is the mechanism of action of lithium?
- Modifies the production and turnover of certain neurotransmitters, particularly serotonin, and may also block dopamine receptors.
- Alters concentrations of certain electrolytes, and may reduce thyroid activity
What are the routes of delivery of lithium?
PO
What are the indications for lithium?
- Acute episodes of mania and hypomania
- Recurrent depression where treatment with other anti-depressants has failed
- Bipolar affective disorder
- Control of aggressive behaviour or intentional self harm
What are the contraindications to lithium?
- Cardiac disease
- Personal or family history of Bruguda syndrome
- Untreated hypothyroidism
- Breastfeeding
Why is lithium contraindicated in untreated hypothyroidism?
Because lithium therapy can cause or exacerbate hypothyroidism
Why is lithium therapy contraindicated in breastfeeding?
Present in breastmilk
When should lithium be used with caution?
- Pregnancy
- Patients with low body sodium levels, e.g. dehydrated, taking low sodium diet
Why should lithium be used with caution in pregnancy?
Risk of fetal cardiac malformation (Epstein’s anomaly)
When should lithium be considered in pregnancy?
If benefit outweighs risk
What medications might lithium interact with to cause increased serum lithium concentration?
- Diuretics
- ACEi and ARBs
- NSAIDs
What medications might lithium interact with to cause reduce serum lithium concentrations?
Sodium chloride supplements
What medications might lithium interact with to cause QT prolongation?
- Amiodarone
- Venlafaxine
What medications might lithium interact with to cause an increased risk of tornadoes de pointes?
- Amiophylline
- Clarithryomycin
What medications might lithium interact with to cause an increased risk of serotonin syndrome?
- SSRIs
- MAOIs
Why is monitoring important with lithium?
Narrow therapeutic window and high toxicity risk
How should lithium be monitored?
- Monitor plasma lithium levels
- Renal function
- BP, weight, BMI
What should plasma lithium levels be?
0.4-1mmol/L
What should be done before starting lithium?
- Measure patients weight
- Check FBC, U&Es, TFTs, GFR, and obtain an ECG
When should lithium levels be checked?
1 week after starting, and every dose adjustment
How long after dose of lithium should levels be checked?
12 hours after last dose
How often should renal function be checked when the patient is on lithium?
Every 6 months