Lithium Flashcards
What is the therapeutic range of lithium (higher and lower end)
- 4 to 1mmol/L (lower end for maintenance and elderly)
0. 8 to 1mmol/L (for acute episodes of mania and relapse patients)
What are the warning signs of lithium that require withdrawal
- Toxicity: serum concentration over 2mmol/L- seizures, comas, renal failure, arrhythmias, BP changes, circulatory failure and death
- Increasing GI disturbances (vomiting and diarrhoea)
- Visual disturbances (blurred vision)
- CNS disturbances (drowsiness, confusion, unsteadiness)
- Fine tremor increasing to coarse tremor- muscle weakness
- Signs and symptoms of hypothyroidism (unexplained fatigue, weight gain, hair loss)
- Signs and symptoms of renal dysfunction (polyuria and polydipsia)
- Signs and symptoms of benign intracranial hypertension (persistent headache and visual disturbance)
What is the monitoring requirements required for lithium
- Serum lithium concentration- weekly then every 3 months once dose becomes stable
- Renal function (every 6 months)
- Cardiac function (every 6 months)
- Thyroid function (every 6 months)
What are the interactions lithium may have with other drugs
Increase risk of toxicity with: ACE inhibitors Angiotensin II receptor antagonists Loop diuretics Thiazide diuretics NSAIDs Potassium-sparing diuretics Metronidazole SSRIs Tricyclics
Increased ventricular arrythmias with amiodarone
Risk of neurotoxicity with: METHYLDOPA Phenytoin Carbamazepine Diltiazem Verapamil
Increased risk of extra pyramidal effects with CLOZAPINE HALOPERIDOL RISPERIDONE PHENOTHIAZIDES ZUCLOPENTHIXOL
What are the cautions of lithium
Long term use means:
Thyroid disorders
Mild cognitive and memory impairment
What other points should you be aware of in lithium
Lithium treatment pack should be given on initiation treatment
Kept on same brand of lithium
Toxicity made worse by sodium depletion so therefore must keep a constant salt and water intake
Avoid NSAIDs and alcohol
Do not stop suddenly unless told to by a doctor (risk of relapse)
