LITHIUM
(Lithmax, extended-release tablet)Standard Prescription
lithium mg PO__(frequency)
Dosages
Dosing is guided by serum level monitoring.
Suggested Target Dose: Adjust daily dose by 150-300 mg increments every 3-4 days to initial target dose of 15 mg/kg/24 hr, then as needed to achieve therapeutic level.
Usual maximum dose: 1800 mg/24 hr.
Adults:
Initial: 450 mg PO BID or 900 mg PO QHS.
Suggested Target Dose: 1200-1800 mg/day div. BID or as single HS dose. Increase gradually at 3-4 day intervals to achieve therapeutic level.
Maximum: 2400 mg/24 hr
Children, Adolescents & Adults:
Maintenance: When dose is stabilized, once daily dosing at HS is preferred if tolerated. "Trough" serum levels drawn reflecting a single daily HS dosage regimen may be 15-20% higher than when same total daily dosage is given in divided doses BID or TID.
Children & Adolescents:
Initial Dose: 150 mg PO BID or 300 mg HSSuggested Target Dose: Adjust daily dose by 150-300 mg increments every 3-4 days to initial target dose of 15 mg/kg/24 hr, then as needed to achieve therapeutic level.
Usual maximum dose: 1800 mg/24 hr.
Adults:
Initial: 450 mg PO BID or 900 mg PO QHS.
Suggested Target Dose: 1200-1800 mg/day div. BID or as single HS dose. Increase gradually at 3-4 day intervals to achieve therapeutic level.
Maximum: 2400 mg/24 hr
Children, Adolescents & Adults:
Maintenance: When dose is stabilized, once daily dosing at HS is preferred if tolerated. "Trough" serum levels drawn reflecting a single daily HS dosage regimen may be 15-20% higher than when same total daily dosage is given in divided doses BID or TID.
Mechanism of Action
Antipsychotic; antimanic agent
Forms Supplied
capsule: 150 mg, 300 mg, 600 mg
extended-release tablet: 300 mg (Extended-release tablets should not be crushed or chewed, but may be split.)
Comments
Desired serum levels: 0.8-1.2 mmol/L
A serum level in upper end of range may be required to control acute mania.
Accuracy of lithium serum level testing is best when drawn >= 5 days after dose change.
Drug follows first-order pharmacokinetics; important to note timing of blood draw.
Increased sodium intake will decrease lithium levels.
Multiple drug interactions.
NSAIDS given concomitantly may decrease renal excretion of lithium and increase lithium toxicity.
Use with caution in patients with cardiovascular disease or medications that alter sodium excretion.
Avoid lithium in renal failure.
Common adverse effects in children include nausea, vomiting, tremor, frequent urination, enuresis, thirst, hypercalcemia, increased TSH level, acne.
Caution: Toxidrome (lithium poisoning) includes severe nausea/vomiting, severe tremor, stupor, ataxia, slurred speech, coma). If suspected, draw serum level immediately and consider ICU admission and hemodialysis. Consult Poison Control centre.
Extended-release tablet may reduce sensitivity/ adverse effects related to high peak levels (tremor, urinary frequency, nausea) 1-2 hr post-dose are observed with immediate release formulation.
Monitor CBC, thyroid, cardiac, renal function every 6-12 months, calcium & parathyroid hormone every 24 months.
References
1, 44, 83, 235, 236
Last Edited
2022-04-04 19:34:08