Lithobid

Action

Unknown. Thought to disrupt sodium exchange and transport in nerves and muscles and control reuptake of neurotransmitters.

Availability

Capsules: 150 mg, 300 mg, 600 mg

Syrup (citrate): 300 mg (8 mEq lithium)/5 ml

Tablets: 300 mg

Tablets (extended-release): 300 mg, 450 mg

Tablets (slow-release): 300 mg

Indications and dosages

➣ Manic episodes of bipolar disorder

Adults and children ages 12 and older: 900 to 1,800 mg P.O. daily in divided doses (for example, 300 to 600 mg t.i.d. or 450 to 900 mg b.i.d. of controlled- or slow-release form) to achieve blood level of 1 to 1.5 mEq/L; measure blood level twice weekly until patient stabilizes. Maintenance dosage is 900 to 1,200 mg/day in divided doses (forexample, 300 to 400 mg t.i.d. or 450 to 600 mg b.i.d. of controlled- or slow-release form) to maintain blood level of 0.6 to 1.2 mEq/L. Monitor blood level at least q 2 months.

Dosage adjustment

• Impaired renal function

• Elderly patients

Off-label uses

• Acute manic episodes in children

• Corticosteroid-induced psychosis

• Neutropenia secondary to antineoplastic therapy

• Tardive dyskinesia

• Alcoholism

• Bulimia

Contraindications

None

Precautions

Use cautiously in:

• hepatic or thyroid disease, severe cardiovascular or renal disease, diabetes mellitus, seizure disorders, systemic infections, brain trauma, organic brain syndrome, urinary retention, severe sodium depletion

• elderly patients

• pregnant or breastfeeding patients

• children (safety not established).

Administration

See Be aware that dosages are individualized according to lithium blood level and response.

• Give with food or milk to minimize GI upset.

• Make sure patient swallows slow-release tablet whole without chewing or crushing.

• When switching patient from immediate-release to controlled- or slow-release form, give same total daily dosage.

Adverse reactions

CNS: dizziness, drowsiness, headache, tremor, tics, EEG changes, ataxia, choreoathetotic movements, abnormal tongue movements, extrapyramidal reactions, cogwheel rigidity, blackout spells, psychomotor retardation, slow mental functioning, slurred speech, startled response, restlessness, agitation, confusion, hallucinations, poor memory, worsening of organic brain syndrome, stupor, coma, epileptiform seizures

CV: bradycardia, ECG changes, hypotension, sinus node dysfunction with severe bradycardia and syncope, arrhythmias, peripheral circulatory collapse

EENT: blurred vision, nystagmus, tinnitus

GI: nausea, vomiting, diarrhea, abdominal pain, fecal incontinence, gastritis, flatulence, dyspepsia, anorexia, increased salivation, salivary gland swelling, dry mouth

GU: urinary incontinence, glycosuria, albuminuria, erectile or other sexual dysfunction, polyuria or other signs of nephrogenic diabetes insipidus, oliguria

Hematologic: leukocytosis

Metabolic: hypothyroidism or hyperthyroidism, goiter, hyperglycemia, hypercalcemia, hyponatremia, hyperparathyroidism

Musculoskeletal: swollen or painful joints, muscle weakness, muscle fasciculations and twitching, clonic arm or leg movements, hypertonicity, hyperactive deep tendon reflexes, polyarthralgia

Skin: dry thin hair, alopecia, diminished or absent skin sensations, chronic folliculitis, eczema with dry skin, new onset or exacerbation of psoriasis, pruritus (with or without rash), cutaneous ulcers, angioedema

Other: altered, metallic, or salty taste; dental caries; weight gain; excessive thirst; polydipsia; fever; edema of lips, ankles, and wrists

Interactions

Drug-drug. Acetazolamide, alkalinizing agents (such as sodium bicarbonate), urea, verapamil, xanthines: decreased lithium blood level

Calcium channel blockers, carbamazepine, haloperidol, methyldopa: increased risk of neurotoxicity

Diuretics: increased sodium loss, increased risk of lithium toxicity

Fluoxetine, loop diuretics, metronidazole, nonsteroidal anti-inflammatory drugs: increased risk of lithium toxicity

Iodide salts: synergistic effects, increased risk of hypothyroidism

Neuromuscular blockers: prolonged neuromuscular blockade, severe respiratory depression

Phenothiazines: decreased phenothiazine blood level or increased lithium blood level, greater risk of neurotoxicity

Selective serotonin reuptake inhibitors: increased risk of tremor, confusion, dizziness, agitation, and diarrhea

Sympathomimetics: decreased pressor sensitivity

Tricyclic antidepressants: increased antidepressant effects

Drug-diagnostic tests. Albumin, creatinine, sodium, thyroxine, triiodothyronine: decreased levels

Calcium, glucose,¹³¹I uptake, white blood cells (WBCs): increased levels

Drug-food. Caffeine-containing foods and beverages: decreased lithium blood level and efficacy

Drug-herbs. Caffeine-containing herbs (cola nut, guarana, yerba maté): decreased lithium blood level and efficacy

Patient monitoring

• Obtain baseline ECG and electrolyte levels before and periodically during therapy.

• Assess neurologic and psychiatric status. Institute safety measures as needed to prevent injury.

• Monitor lithium blood level, WBC count, and thyroid and kidney function tests.

• Assess cardiovascular status regularly.

• Monitor fluid intake and output. Watch for edema and weight gain.

Patient teaching

• Advise patient to take with food or milk to minimize GI upset.

• Instruct patient to swallow slow-release tablet whole without chewing or crushing.

• Tell patient that beneficial effects may take 1 to 3 weeks to appear.

• Advise patient to limit foods and beverages containing caffeine, because they may interfere with drug action.

• Tell patient to maintain adequate fluid intake.

• Explain that drug may cause adverse CNS effects. Advise patient to avoid activities requiring mental alertness until effects are known.

See Emphasize importance of having regular blood tests, to help detect and prevent serious adverse reactions.

• Instruct patient to carry appropriate medical identification at all times.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and herbs mentioned above.