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Psychopharmacology
Lithium carbonate : Nursing implications
Last updated on
22-08-09
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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 necessary
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.
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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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