Levomepromazine Orion (Levomepromazine)

Levomepromazine is used in several psychiatric and supportive‑care pathways to control symptoms related to dopamine dysregulation and nausea.

• Schizophrenia and other psychotic disorders: reduces hallucinations, delusions, and thought disorder, helping stabilize mental status.
• Severe anxiety and agitation: provides rapid calming effect, useful in acute distress or pre‑operative settings.
• Nausea and vomiting in palliative care: controls refractory emesis when other anti‑emetics are insufficient.
• Pre‑operative sedation: produces sedation and anxiolysis before surgical procedures.

• Levomepromazine acts primarily as a dopamine D2 receptor antagonist, decreasing dopaminergic neurotransmission in mesolimbic pathways. In addition, it blocks histamine H1, muscarinic acetylcholine, and alpha‑adrenergic receptors, producing antihistaminic, anticholinergic, and vasodilatory effects. The antagonism at these sites also contributes to reductions in nausea signaling from the chemoreceptor trigger zone and to the calming of central nervous system excitability.

Levomepromazine may cause a range of adverse reactions, varying from mild to potentially serious.

Common Side Effects

• Drowsiness or sedation: feeling unusually sleepy or sluggish.
• Dry mouth: reduced salivation causing discomfort.
• Constipation: slowed intestinal motility leading to hard stools.
• Orthostatic hypotension: drop in blood pressure upon standing, causing dizziness.
• Blurred vision: temporary visual disturbance.

Serious or Rare Side Effects

• Extrapyramidal symptoms (e.g., dystonia, parkinsonism): involuntary muscle movements or rigidity.
• Neuroleptic malignant syndrome: rare life‑threatening reaction with fever and muscle rigidity.
• Severe hypotension or cardiac arrhythmias: dangerous drops in blood pressure or irregular heartbeats.
• Agranulocytosis or severe leukopenia: marked reduction in white blood cells, increasing infection risk.

When prescribing Levomepromazine, clinicians should observe several safety considerations to minimize risk.

• Assess cardiovascular status: monitor blood pressure and heart rate for orthostatic changes.
• Evaluate hepatic and renal function: adjust use in patients with significant impairment.
• Screen for history of seizures or movement disorders: increased risk of extrapyramidal effects.
• Avoid abrupt discontinuation: taper gradually to reduce withdrawal or rebound agitation.
• Use caution in elderly patients: heightened sensitivity to sedation and hypotension.
• Store at ambient temperature below 25 °C: keep in original container, protect from moisture and light.

Levomepromazine can interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Other dopamine antagonists (e.g., antipsychotics, metoclopramide): additive CNS depression and increased extrapyramidal risk.
• QT‑prolonging agents (e.g., certain antiarrhythmics, macrolide antibiotics): heightened risk of cardiac arrhythmias.

Moderate Interactions (Monitor Closely)

• CNS depressants (e.g., benzodiazepines, opioids): enhanced sedation and respiratory depression.
• Anticholinergic drugs (e.g., atropine, antihistamines): may intensify dry mouth, constipation, and blurred vision.
• CYP2D6 inhibitors (e.g., fluoxetine, quinidine): can raise levomepromazine plasma levels, requiring dose adjustment.