Introduction
Since the 1950s, lithium salts have been the
main line of treatment for bipolar disorder (BD), both as a
prophylactic and as an episodic treatment agent. Response to lithium
seems to cluster in families and can be used as a predictor for
recurrence of BD symptoms. (Cruceanu C, 2009), Bipolar disorder is often
treated with what are called mood stabilizers, which include lithium,
valproate, or carbamazepine. These medications can be very effective
in treating hypomania or mania and preventing the recurrence of
bipolar episodes. Lithium therapy remains a key component in the
treatment of psychiatric conditions where the main symptoms are mood
changes. As with many psychotropic drugs, lithium requires strict
monitoring as it works within a relatively narrow therapeutic range -
too little and it will be ineffective, too much and it could be toxic.
Patients who are prescribed lithium must have access to robust
monitoring protocols to reduce the risk of physical harm caused by
toxicity.
Mood stabilizer
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Preparations:-Capsules: 150 mg, 300 mg, 600 mg. Tablets: 300 mg. Tablets (slow-release): 300 mg, 450 mg. Syrup: 300 mg/5 ml
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Pharmacokinetics:-Rapid, complete absorption from GI tract. Primarily excreted unchanged in urine. Half-life: 18–24 hrs (increased in elderly)
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Mechanism of action:
Alters ion transport at cellular sites in body tissue. Cations
necessary in synthesis, storage, release, reuptake of
neurotransmitters involved in producing antimanic, antidepressant effects
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Theraaputic uses: Prophylaxis, treatment of acute mania, manic phase of bipolar disorder (manic-depressive illness). Treatment of mental depression, prophylaxis of vascular headache, treatment of neutropenia
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Doses-During
acute phase, therapeutic serum lithium concentration of 1–1.4 mEq/L
is required. Desired level during long-term control: 0.5–1.3 mEq/L.
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Contraindications: Severe cardiovascular disease, severe renal disease, severe dehydration/sodium depletion, debilitated patients.
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Cautions: Cardiovascular disease, thyroid disease, elderly
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Pregnancy/lactation: Freely crosses placenta; distributed in breast milk
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Drug Ineractions:-May
increase effects of antithyroid medication, iodinated glycerol,
potassium iodide. NSAIDs may increase concentration, toxicity. May
decrease absorption of phenothiazines. Phenothiazines may increase
intracellular concentration, increase renal excretion, extrapyramidal
symptoms (EPS), delirium, mask early signs of lithium toxicity.
Diuretics may increase concentration, toxicity. Haloperidol may
increase EPS, neurologic toxicity. Molindone may increase risk of
neurotoxic symptoms.
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Side effects:
- high incidence: polyuria (increased urination), polydipsia
(excessive thirst) due to reversible diabetes insipidus. Frequent: dry
mouth, lethargy, fatigue, muscle weakness, headache, GI disturbances
(mild nausea, anorexia, diarrhea, abdominal bloating), fine hand
tremor, and inability to concentrate. rare: muscle hyperirritability
(hyperactive reflexes, twitching), vertigo, hypothyroidism
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Adverese reactions: -Serum lithium
concentration of 1.5–2.0 mEq/L may produce vomiting, diarrhea,
drowsiness, incoordination, coarse hand tremor, muscle twitching, EKG
T-wave depression, mental confusion. Serum lithium concentration of
2.0–2.5 mEq/L may result in ataxia, giddiness, tinnitus, blurred
vision, clonic movements, severe hypotension. Acute toxicity
characterized by seizures, oliguria, circulatory failure, coma, death.
Nursing Care
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Baseline evaluation of the patient including ECG, liver function test, renal function test.
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Serum lithium levels should be tested every 3–4
days during initial phase of therapy, every 1–2 mos thereafter, and
weekly if there is no improvement of disorder or adverse effects
occur.
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Lithium serum testing should be performed as close as possible to 12th hour after last dose.
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Besides serum lithium concentration levels,
clinical assessment of therapeutic effect or tolerance to drug effect
is necessary for correct dosing-level management.
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mental status examination including assessment of
behavior, appearance, emotional status, response to environment,
speech pattern, thought content are done frequently to monitor
therapeutic effect.
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Monitor serum lithium concentrations,
differential count, urinalysis, creatinine clearance are done
regularly based on the treatment guidelines and depending on the
physical status of the patient, financial position and on development
of suspected adverse effects.
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Assess for increased urine output, persistent
thirst is important. Any polyuria, prolonged vomiting, diarrhea, fever
to physician (may need to temporarily reduce or discontinue dosage)
should be reported to the treating physician.
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Monitor for signs of lithium toxicity. Supervise
suicidal risk pt closely during early therapy (as depression lessens,
energy level improves, and suicide potential increases).
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Assess for therapeutic response (interest in
surroundings, improvement in self-care, increased ability to
concentrate, relaxed facial expression).
Patient/Family Teaching Points
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Take as directed; do not discontinue except on physician’s advice.
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Do not engage in activities requiring alert response until effects of drug are known.
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Thirst, frequent urination may occur.
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A fluid intake of 2–3 quarts liquid per day and
maintenance of a normal salt intake are necessary during initial phase
of treatment to avoid dehydration.
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Thereafter, 1–1.5 L fluid intake daily is necessar
References
- Benjamin JS, Sadock UA. Comprehensive text book of psychiatry. Lippincott Williams & wilkins; Philadelphia: 2005.
- Niraj Ahuja. A short text book of Psychiatry Jaypee brothers medical publishers; New Delhi: 2006.
- Katherine MF, Worret PAH. Psychiatric mental health nursing. Mosby, St. louis : 2008.
- Cruceanu C, Alda M, Turecki G.Lithium: a key to the genetics of bipolar disorder.Genome Med. 2009 Aug 19;1(8):79.
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