Lithium
Mechanism :
Studies have shown that lithium alters sodium transport in nerve and muscle cells and effects a shift toward intraneuronal metabolism of catecholamines, but the specific biochemical mechanism of lithium action in mania is unknown.
Indication :
- Acute manic disorder
- Bipolar disorder (off-label)
Contraindications :
Use with caution in renal insufficiency, thyroid disease and adrenocortical deficiency. Do not prescribe unless monitoring available. Check blood pressure, electrolytes, renal and thyroid function before commencing treatment and 6 monthly thereafter.
Dosing :
Under 6 years:
Safety and efficacy not established.
6-12 years:
15-60 mg/kg/day orally in 3-4 divided doses; not to exceed adult dosage
Above 12 years:
100 mg/m² orally once every 6 weeks.
Maintain plasma level of 0.4-1 mmol/L 12 hours after last dose. Monitor once in 3 months.
Adverse Effect :
Fine hand tremor, polyuria, mild thirst, transient and mild nausea, general discomfort, leucocytosis, dry mouth, headache, decreased memory, confusion, muscle weakness (initially), ECG changes, vomiting, diarrhea, hyperreflexia, vertigo, extrapyramidal symptoms, goitre, hypothyroidism, acne, hair thinning.
Interaction :
Diuretics: Caution should be used when lithium and diuretics are used concomitantly because diuretic-induced sodium loss may reduce the renal clearance of lithium and increase serum lithium levels with risk of lithium toxicity.
NSAID: Lithium toxicity has resulted from interactions between an NSAID and lithium.
Metronidazole: May provoke lithium toxicity due to reduced renal clearance. Patients receiving such combined therapy should be monitored closely.
Angiotensin-converting enzyme inhibitors: May substantially increase steady-state plasma lithium levels.
Calcium Channel Blocking Agents: May increase the risk of neurotoxicity in the form of ataxia, tremors, nausea, vomiting, diarrhea and/or tinnitus.
Selective Serotonin Reuptake Inhibitors: This combination has been reported to result in symptoms such as diarrhea, confusion, tremor, dizziness, and agitation.
Acetazolamide, Urea, Xanthine Preparations and Alkalinizing Agents such as Sodium Bicarbonate: Can lower serum lithium concentrations by increasing urinary lithium excretion.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Avoid if possible, or reduce dose and monitor plasma concentration carefully |
| 10-20 | Avoid if possible, or reduce dose and monitor plasma concentration carefully |
| <10 | Avoid if possible, or reduce dose and monitor plasma concentration carefully |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Dialysed in lithium intoxication. Dose as in GFR<10 mL/min |
| HD | Dialysed in lithium intoxication. Dose as in GFR<10 mL/min |
| HDF/High flux | Dialysed in lithium intoxication. Dose as in GFR<10 mL/min |
| CAV/VVHD | Dialysed. Dose as in GFR=10– 20 mL/min |
Hepatic Dose :
No dose adjustments are recommended. Dose adjustment may be needed if patient has hyponatremia or hypernatremia, dehydration, is on diuretics.