Lithium

Current IR carbonate and oral-solution labels indicate monotherapy for acute manic/mixed episodes and maintenance of bipolar I disorder in patients ≥7. Selected ER 450 mg and Lithobid 300 mg labels describe manic-episode treatment and maintenance of bipolar disorder, with safety / effectiveness below 12 unestablished and use there not recommended. IR pediatric approval does not automatically update an ER label. Depression augmentation, suicide-prevention claims or a preferred guideline ranking are not inferred from these product indications.

Selected ER 450 mg and Lithobid 300 mg labels describe acute doses commonly 1800 mg/day in divided doses and maintenance commonly 900–1200 mg/day. Their acute target text is 1.0–1.5 mEq/L and maintenance 0.6–1.2, whereas current IR/solution targets are 0.8–1.2 and 0.8–1.0. The ER acute upper value overlaps the labels’ toxicity threshold of ≥1.5; it is reported as a source difference, not a recommended target to approach. Prescriber / pharmacist must select a safe product / phase / patient-specific target. No independent universal maximum, age-7 ER regimen or conversion based only on a serum goal is supplied.

Swallow selected ER tablets whole; never chew/crush. ER 450 mg usually uses twice-daily doses about 12 hours apart. Its label permits the same total daily dose when switching IR if achievable; if not a 450 mg multiple, choose the nearest lower multiple under prescriber control, with larger unequal dose in evening. For example the label switches 1500 mg/day IR to 1350 mg/day ER (450 morning/900 evening), with monitoring at 1–2-week intervals until stable. Use IR if finer titration is needed. Lithobid has its own 300 mg unit/regimens; do not copy 450 mg rounding to it. ER labels specify 8–12-hour pre-dose sampling, twice-weekly acute checks and at least every 2 months for uncomplicated stable maintenance. Current IR/solution specify 12 hours; preserve exact-product sampling plans.

Current IR/solution: CrCl 30–89 mL/min by Cockcroft–Gault starts below normal dosing, titrates slowly and monitors levels/toxicity frequently; CrCl <30 is not recommended. No fixed renal percentage or hepatic formula is supplied. Pregnancy continuation requires changing-clearance monitoring; these labels advise clinician-directed reduction / discontinuation 2–3 days before expected delivery and restarting preconception dose after delivery when medically stable with close levels. Obstetric / psychiatric coordination is essential; this is not a self-directed stop/restart plan.

Current selected IR/solution labels formally contraindicate known hypersensitivity to inactive ingredients. Selected ER labels provide no separate formal contraindications section, but warn against high-risk use and require assessment of severe renal disease, Brugada syndrome and other toxicity risks. “Not recommended” renal or pediatric wording is not silently rewritten as a formal section-4 contraindication; lack of such a section does not establish safety.

All selected labels warn that toxicity is closely related to serum lithium concentrations and can occur at doses near therapeutic concentrations. Facilities for prompt accurate serum measurement must be available before starting treatment. Clinical signs and risk changes matter alongside the measured concentration.

Common early effects include fine tremor, thirst/polyuria, nausea and discomfort; these can overlap toxicity signals. More serious reported effects include neurologic injury, rhythm/conduction changes, renal disease, endocrine abnormalities and severe skin/allergic reactions. Reported-event frequency/causality cannot always be established. Suspected poisoning needs immediate emergency/Poison Help assessment, stopping further lithium and professional supportive care. No specific antidote exists; severe toxicity may need hemodialysis and serial levels because rebound can occur. Activated charcoal does not adequately bind lithium; no home decontamination or self-restart instruction is supplied.

Serotonergic agents, including SSRIs/SNRIs, triptans, tramadol/fentanyl, buspirone, St. John’s wort and MAOIs, can cause serotonin syndrome; counsel/monitor and urgently stop implicated agents if it occurs. Antipsychotics can cause neurotoxicity or encephalopathic / NMS-like reactions. Calcium-channel blockers may increase neurologic effects; methyldopa, phenytoin or carbamazepine may increase adverse reactions. Prolonged iodide use can cause hypothyroidism. Lithium prolongs neuromuscular-blocker effects; tell the anesthesia team. No universal drug-combination dose multiplier is supplied.

Current IR/solution use Cockcroft–Gault CrCl 30–89 lower/slower dosing with frequent monitoring; severe <30 not recommended. Older adults often need lower doses and can be toxic at levels younger adults tolerate. Lithium is not metabolized; no dedicated hepatic adjustment is supplied, but sodium/fluid balance and comorbid renal/cardiac disease remain important. ER formulations require their own clinical / level-based plan; absent numeric renal categories in older ER labeling are not permission to disregard kidney risk.

IR/solution bipolar I monotherapy efficacy established at 7–17; below 7 unestablished. Selected weight regimens begin at 20 kg; no <20 kg titration inferred. Selected ER labels have below-12 safety / effectiveness unestablished and use not recommended; no automatic ER pediatric approval from the ingredient or IR label.

Lithium may harm the fetus, including a potentially small cardiac-malformation risk whose exact magnitude is uncertain. Consider fetal echocardiography at 16–20 weeks after first-trimester exposure per current IR/solution labels. Maternal/neonatal toxicity can occur late in pregnancy / postpartum; use specialist dose/level planning and monitor exposed newborns. Breastfeeding is not recommended in current selected IR/solution labels. If chosen after specialist assessment, closely monitor infant toxicity, lithium and thyroid function and stop breastfeeding if toxicity develops. ER labels reserve nursing for exceptional circumstances after weighing risks; no blanket safety guarantee.

The mood-stabilizing mechanism is unknown. Preclinical effects on ion transport and neurotransmitter metabolism do not establish a complete human clinical mechanism or explain an individual response.

Absorption

Lithium is absorbed orally; IR preparations peak about 0.25–3 hours and sustained-release preparations about 2–6 hours.

Distribution

Approximates total body water; negligible protein binding. Brain distribution may lag blood concentration.

Elimination

No metabolism; primarily renal excretion with substantial tubular reabsorption. Current IR/solution half-life about 18–36 hours; renal function and sodium balance affect clearance.

Sampling

Use the exact product/clinician’s pre-dose interval: current IR/solution 12 hours; selected ER 8–12 hours. A randomly timed result is not interpreted as an equivalent trough.

Salt versus ion

Carbonate mg, citrate-solution mEq and serum mEq/L describe different quantities; verify units before a conversion.

Before initiation assess renal function, vital signs, electrolytes, thyroid function, other medicines and pregnancy potential. Monitor serum lithium regularly and after dose/interaction changes, significant exercise changes or intercurrent illness; clinical signs accompany every interpretation. Check renal function during treatment, thyroid before treatment/at 3 months/every 6–12 months (more often if abnormal), and calcium regularly per current IR/solution labels. Monitor mood/mania response, tremor, coordination, fluid/sodium status and toxicity signals. Selected ER sampling and monitoring intervals remain distinct as shown in Dosage; no universal ECG requirement or identical visit schedule is inferred.

Take only the prescribed product/dose; verify lithium-ion versus salt units and measure solution accurately. Swallow ER whole. Do not double a missed dose or change dose based on symptoms/levels without the prescriber. Keep usual salt intake and a clinician-agreed hydration plan; contact the clinician during fever, heavy sweating, vomiting/diarrhea or reduced intake. Avoid adding OTC NSAIDs or other interacting medicines without review. Stop lithium and promptly seek assessment for toxicity signs; severe symptoms need emergency help. Discuss pregnancy / breastfeeding and lab timing; be cautious driving until effects are known.

Ingredient / route

Lithium carbonate 300 mg · immediate-release oral tablet.

Appearance / imprint

White to off-white biconvex, scored; 54 452.

Example NDC / labeler

0054-0886-25 · 100 tablets, Hikma.

U.S. status

Prescription mood stabilizer; no DEA schedule.

Selected IR

300 mg tablets; capsules 150 mg white (54 213), 300 mg light pink (54 463), 600 mg pink/white (54 702).

Selected citrate solution

8 mEq lithium ion per 5 mL, clear colorless; NDC 72888-172-46, 500 mL, Advagen/Rubicon. Equivalent lithium content to 300 mg carbonate per 5 mL, not 300 mg elemental lithium.

Lithobid ER 300 mg

Peach film-coated tablet, LITHOBID 300; ANI NDC 62559-280-01, bottle 100.

Selected ER 450 mg

Speckled off-white/yellow round biconvex, scored,54 346; RemedyRepack NDC 70518-4678-00, 30-tablet blister.

Scope

Verify exact manufacturer, release form and monitoring plan before switching. ER 300/450 mg tablet units differ; no liquid, IR or ER automatic interchange from appearance alone.

Selected IR and solution 20–25°C, excursions 15–30°C; tight child-resistant container, protect IR from moisture. Lithobid 15–30°C, protected from moisture in tight child-resistant container. Selected ER 450 mg 20–25°C. Keep ER tablets whole, retain package/Medication Guide and verify strength/release form on refill. Store securely away from children; no unsupported refrigeration or after-opening discard interval is supplied.