Bipolar (Lithium) Flashcards
Initial monitoring of lithium
Take samples after 12 hrs after 1st dose to achieve a c con of 0.4-1.0 mmol/l (lower range for maintenance therapy and elderly patients)
Target serum lithium concentration for acute episodes of mania/hx of relapse/ patients with sub syndromal symptoms
0.8-1.0 mmol/l
Monitoring frequency of lithium
After initiation and after dose changes until stable then every 3 months for 1 year and 6 monthly thereafter
When would monitoring be more frequent in lithium patients
Monitor every 3 months in :
- 65+
- Possible DDI with lithium
- Risk of impaired renal or thyroid function function
- Raised calcium levels
- Poor symptom control/adherence
- Previous serum lithium conc >0.8
What to monitor before treatment with lithium
Renal, cardiac, thyroid, BMI, serum electrolytes, FBC
ECG in patients with CVD/CVD risk factors
what to monitor on lithium
Body weighT/BMI
Serum electrolytes
EGFR
Thyroid function
Drugs that increase lithium levels (toxicity)
NSAIDs (e.g. ibuprofen, naproxen)
→ Reduce renal clearance of lithium
ACE inhibitors (e.g. ramipril, enalapril)
→ Reduce lithium excretion via the kidneys
Angiotensin II receptor blockers (ARBs) (e.g. losartan)
→ Similar effect to ACE inhibitors
Diuretics
Especially thiazides (e.g. bendroflumethiazide)
→ Promote sodium loss, increasing lithium reabsorption
Loop diuretics (e.g. furosemide) can also increase risk, but to a lesser extent
Dehydration / Low sodium intake
→ Enhances lithium reabsorption in the kidneys
Drugs that decrease lithium levels
Theophylline
Caffeine
→ Both may increase lithium clearance, decreasing the effectiveness
Other lithium interactions
⚠️ Other Important Interactions
Antipsychotics (especially clozapine, haloperidol)
→ Combined use can ↑ risk of neurotoxicity and extrapyramidal symptoms (EPS)
SSRIs, TCAs, MAOIs
→ Combined with lithium increases risk of serotonin syndrome
Carbamazepine
→ Increased risk of neurotoxicity (e.g. ataxia, confusion, seizures)
Methyldopa and verapamil
→ Can increase lithium levels and neurotoxicity risk
SE of lithium
Tremor
Hypothyroidism (can continue if occurs just treat with thyroxine)
N+V+D
Weight gain
Nephrotoxicity
Electrolyte imbalance
ECG changes
QT PROLONGATION
