From the FDA Drug Label
DOSAGE AND ADMINISTRATION Acute Mania: Optimal patient response to lithium carbonate usually can be established and maintained with 600 mg t.i.d.. Such doses will normally produce an effective serum lithium level ranging between 1 and 1. 5 mEq/L. N.B.: Blood samples for serum lithium determination should be drawn immediately prior to the next dose when lithium concentrations are relatively stable (i.e., 8-12 hours after the previous dose).
The administration time of lithium (lithium carbonate) is not explicitly stated in the drug label.
- Key point: The label mentions that blood samples should be drawn 8-12 hours after the previous dose, implying that lithium levels are relatively stable at this time.
- However, this information does not directly answer the question of administration time. 1
From the Research
Lithium should typically be administered in the evening, preferably with food or after meals, to minimize awareness of early side effects and improve tolerability. For most patients, a once-daily dosing schedule in the evening is recommended, though some may require divided doses (morning and evening) depending on their specific needs and tolerance 2. When starting lithium therapy, begin with a low dose and gradually increase based on blood levels and clinical response. Taking lithium with food helps reduce gastrointestinal side effects like nausea.
Key Considerations
- Evening administration is preferred because it minimizes awareness of early side effects like tremor or mild cognitive effects that may occur at peak blood levels.
- Blood level monitoring is essential, with therapeutic levels typically ranging from 0.6-1.2 mEq/L, though lower levels (0.6-0.8 mEq/L) are often effective for maintenance therapy 3.
- Consistency in timing is important for accurate blood level measurements, which should be drawn 12 hours after the last dose during the steady state.
- A single daily dose of lithium can be a viable method to reduce the side effects of lithium, which may lead to better patient compliance 4.
- The optimal frequency of lithium administration should consider the unique pharmacokinetic and pharmacodynamic properties of lithium, as well as its adverse-effect and toxicity profiles 5.
Administration Schedule
- For patients receiving once-daily administration, the serum concentration at 24 hours should serve as the control value 2.
- With sustained-release preparations, it is advised to keep serum concentrations within the upper range (0.8-1 mmol/L), rather than 0.6-0.8 mmol/L for standard formulations 2.
Special Considerations
- Lithium treatment may inhibit thyroid hormone release and induce goitre, and the prevalence of both overt and subclinical hypothyroidism is increased 6.
- Long-term lithium treatment may also be associated with persistent hyperparathyroidism and hypercalcaemia, as well as with hypermagnesaemia 6.
- Overweight of up to 4-10 kg is found in approximately 30% of lithium-treated patients 6.
- Most neurological manifestations are benign, but a number of rare, potentially serious neurological adverse effects have been reported, including extrapyramidal symptoms, 'pseudotumour cerebri' or occasionally cerebellar symptoms 6.