Formal written procedures / guidelines for doctors and written instructions for patients on lithium are a priority and a benchmark for 'good clinical practice'.
It is my preferred practice to supervise Bipolar Disorder patients and arrange tests myself. But, whoever is participating in the care, there needs to be a clear instruction about who is responsible for what (see 'general update' note).
It is recommended that there be a specialist letter with a formal diagnosis and plan for type and frequency of visits and tests, especially if different from standard guidelines; and noting risk factors relevant to tests:- eg age, gender, medical history. Copies of all investigations always to be sent to both doctors.
If GP practices are taking primary management responsibility then ensure there is written documentation on the case record, up to date guidelines and a nominated doctor responsible.
If hospital / private specialist is taking management responsibility then ensure there is a clear note to that effect displayed on the patient case notes.
Do not issue a Lithium script without:--
- Checking there is a specialists letter on file giving clear diagnosis and treatment advice and specialist review date.
- Checking one nominated doctor is responsible for issuing scripts and monitoring tests etc (usually a specialist).
- Seeing the patient; checking they have been / are attending follow up/ referring them on to who is responsible.
- Checking patients have written information / instructions.
- If issuing an urgent script only prescribe sufficient lithium to last till the next essential monitoring visit / blood test.
- If relevant tests are performed for other reasons be sure to send copies to specialist.
- Note any drugs affecting lithium-- ACE inhibitors, NSAIDs and diuretics (especially thiazide)
Guidelines on Lithium monitoring
- Three monthly: doctor / specialist consultation and lithium level.
- 6-12 monthly: Both T4 and TSH
- 12 monthly: creatinine (and estimated creatinine clearance), E & U, Ca++. In at risk groups early morning urine osmolality / 24 hr urine volume and consider full creatinine clearance.
- 12 monthly: Weight, BP and pulse, urine dipstick.
- Special review before major surgery etc, especially renal function and NDI (nephrogenic diabetes insipidus)
- Variations in these intervals will be influenced by eg: age, gender, medical history of risk factors, illness severity, previous illness course etc.
Routine plasma estimations must be done 12 hours after the last dose. Levels between 0.4 and 0.8 mmol/L are usually suitable for prophylaxis; toxicity does occur within that range.
Lithium is never stopped suddenly, because of the risk of rebound mania. Reduce by 25% of the dose, or 250 mg, every 6 - 8 weeks.