LITHOTABS
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LITHOTABS (LITHOTABS).
Lithium modulates neurotransmitter receptors, second messenger systems, and ion transport pathways; it inhibits inositol monophosphatase, leading to reduced inositol triphosphate and altered neuronal signaling; also affects glycogen synthase kinase-3 (GSK-3) activity and enhances neuroprotective pathways.
| Metabolism | Lithium is not metabolized; it is excreted unchanged primarily by the kidneys (approx. 95% via renal clearance). Reabsorption in the proximal tubule is influenced by sodium balance; thiazide diuretics, NSAIDs, and ACE inhibitors can increase serum levels. |
| Excretion | Renal: >95% as unchanged drug; <1% fecal via bile; minor sweat/saliva |
| Half-life | 18-24 hours (terminal); prolonged in elderly, renal impairment, or dehydration; shorter in younger patients (12-14 hours); requires monitoring for narrow therapeutic index |
| Protein binding | 0% (not bound to plasma proteins) |
| Volume of Distribution | 0.7-1.0 L/kg; distributes into total body water, crosses placenta and blood-brain barrier |
| Bioavailability | Oral: 80-100% (immediate-release); 60-80% (extended-release, varies with formulation) |
| Onset of Action | Oral: 1-3 hours for acute effects; steady-state reached in 5-7 days |
| Duration of Action | 24-36 hours for mood stabilization; requires daily dosing due to narrow therapeutic window |
300-600 mg orally 2-3 times daily, titrated to serum lithium levels of 0.6-1.2 mEq/L.
| Dosage form | TABLET |
| Renal impairment | GFR 30-59 mL/min: reduce dose by 50% and monitor levels. GFR <30 mL/min: contraindicated. |
| Liver impairment | No specific adjustment required; monitor lithium levels due to potential fluid/electrolyte imbalances. |
| Pediatric use | 15-20 mg/kg/day orally in 3 divided doses, titrated to serum levels 0.6-1.2 mEq/L; not recommended under 7 years. |
| Geriatric use | Start at lower dose (150-300 mg/day) with gradual titration; target serum levels 0.4-0.8 mEq/L; monitor renal function and drug interactions. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for LITHOTABS (LITHOTABS).
| Breastfeeding | Lithium is excreted into breast milk (M/P ratio ~0.3-0.5). Infant lithium levels approximately 10-50% of maternal serum levels. Potential for infant toxicity (hypotonia, cyanosis, ECG changes). Breastfeeding generally not recommended due to risk; if attempted, monitor infant serum lithium levels and thyroid function. |
| Teratogenic Risk | First trimester: Increased risk of Ebstein's anomaly (1-2/1000 vs 1/20000 baseline) and other cardiac defects. Second/third trimester: Fetal goiter, neonatal hypothyroidism, diabetes insipidus, preterm delivery, and perinatal mortality. Risk of fetal toxicity increases with maternal serum lithium levels >1.0 mEq/L. |
■ FDA Black Box Warning
Lithium toxicity is closely related to serum concentrations and can occur at doses close to therapeutic levels. Monitoring of serum lithium levels is required to avoid toxicity. Risks include renal impairment, neurotoxicity, thyroid abnormalities, and cardiac effects.
| Common Effects | Nausea Diarrhea Dryness in mouth Fatigue Headache Skin rash Sleepiness Vomiting |
| Serious Effects |
["Severe renal impairment (creatinine clearance < 30 mL/min) or acute renal failure.","Severe cardiovascular disease (e.g., acute myocardial infarction, advanced heart block).","Untreated hypothyroidism (relative).","Sodium depletion (relative).","Breastfeeding (absolute in some guidelines).","Pregnancy, especially first trimester (relative; must weigh risks/benefits)."]
| Precautions | ["Renal toxicity: chronic use may cause interstitial nephritis and impaired concentrating ability.","Neurotoxicity: tremors, ataxia, confusion, seizures (risk increased with high serum levels).","Thyroid dysfunction: hypothyroidism or goiter (monitor thyroid function).","Cardiac effects: T-wave changes, arrhythmias (caution in patients with pre-existing cardiac disease).","Dehydration and hyponatremia: increase risk of lithium toxicity.","Pregnancy: risk of Ebstein's anomaly and other teratogenic effects (especially first trimester).","Lactation: excreted in breast milk; potential for infant toxicity."] |
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| Fetal Monitoring | Monitor maternal serum lithium levels monthly (more frequently in third trimester) to maintain therapeutic levels (0.6-1.2 mEq/L). Renal function (serum creatinine) and thyroid function tests (TSH, free T4) every trimester. Fetal ultrasound for cardiac anatomy at 18-22 weeks. Neonatal assessment: Electrolytes, glucose, thyroid function, and ECG after birth. |
| Fertility Effects | Lithium may cause menstrual irregularities in women and reduced sperm motility in men; however, no definitive evidence of impaired fertility. Effects are reversible upon discontinuation. |