Generic Name

Levomepromazine

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Classification

FDA Approved Indications

• Schizophrenia
• Severe nausea and vomiting
• Preoperative sedation
• Agitation in terminally ill patients

Mechanism of Action

Levomepromazine acts by blocking dopamine D2 receptors in the central nervous system, which results in antipsychotic effects; it also antagonizes other neurotransmitter receptors, such as histamine H1, alpha-adrenergic, and cholinergic receptors, contributing to sedation and various side effects.

Dosage and Administration

Adult: Dose varies; typically 25-100 mg orally three times daily or as directed by a physician. For agitation or nausea, lower doses may be used.

Pediatric: Not generally recommended due to limited safety data.

Geriatric: Start with lower doses due to increased sensitivity and risk of adverse effects.

Renal Impairment: Adjust dose based on clinical response and tolerability.

Hepatic Impairment: Use with caution; dose adjustment may be necessary.

Pharmacokinetics

Absorption: Well absorbed orally.

Distribution: Widely distributed across body tissues, crosses the blood-brain barrier.

Metabolism: Metabolized primarily in the liver via CYP enzymes.

Excretion: Excreted mainly in the urine as metabolites.

Half Life: Approximately 24 hours, varies with individual.

Contraindications

• Known hypersensitivity to phenothiazines.
• Coma or CNS depression.
• Parkinson's disease.

Precautions

• Use with caution in elderly, to prevent falls; in patients with cardiovascular disease, prostate hypertrophy, hepatic impairment, or epilepsy. Monitor for extrapyramidal symptoms and tardive dyskinesia. Report signs of neuroleptic malignant syndrome. Not recommended during pregnancy unless benefits outweigh risks; unknown safety during breastfeeding.

Adverse Reactions - Common

• Sedation (Common)
• Orthostatic hypotension (Common)
• Dry mouth (Common)
• Extrapyramidal symptoms (Less common)

Adverse Reactions - Serious

• Neuroleptic malignant syndrome (Rare)
• QT prolongation and arrhythmias (Rare)
• Agranulocytosis or leukopenia (Rare)

Drug-Drug Interactions

• CNS depressants (enhanced sedative effect)
• Other antipsychotics (risk of additive side effects)
• Antihypertensives (potentiation of hypotensive effects)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Take medication exactly as prescribed.
• Report any excessive sedation, movement disorders, or signs of allergic reactions.
• Avoid alcohol and CNS depressants.
• Do not operate heavy machinery until effect is known.

Special Considerations

Black Box Warnings:

• Elderly patients with dementia-related psychosis are at increased risk of death.

Genetic Factors: Consider pharmacogenetic testing for sulfation capacity which may affect drug metabolism.

Lab Test Interference: May cause false positives in certain liver function or electrolyte tests.

Overdose Management

Signs/Symptoms: Severe sedation, hypotension, extrapyramidal symptoms, agitation, seizures, coma.

Treatment: Supportive care, stabilization of vital signs, activated charcoal if ingestion was recent, gastric lavage in certain cases, and symptomatic treatment. Consider use of bromocriptine or dantroline for neuroleptic malignant syndrome.

Storage and Handling

Storage: Store at room temperature away from light and moisture.

Stability: Stable under recommended conditions for shelf life specified by manufacturer.