Emitab

Approved Indications

• Nausea and Vomiting (Severe or Refractory)
  • Control of severe nausea and vomiting from various causes (e.g., postoperative, drug-induced, cancer chemotherapy, radiation therapy, infectious gastroenteritis).
• Schizophrenia and Other Psychotic Disorders
  • Treatment of schizophrenia, including acute psychosis and chronic forms.
  • May be used for delusional disorders, schizoaffective disorder, and paranoid states.
• Acute Anxiety (Short-Term Use)
  • Short-term management of severe anxiety not responsive to standard anxiolytics.
  • Often used when rapid tranquilization is needed in hospitalized settings.
• Vertigo-Associated Disorders
  • Relief of dizziness and vertigo due to Ménière’s disease and other vestibular disturbances.

Clinically Accepted Off-Label Uses

• Migraine-Associated Nausea and Headache Relief
  • Frequently used in emergency settings for acute migraine attacks, especially with associated nausea/vomiting.
• Agitation in Dementia or Acute Behavioral Disturbances (Specialist Use Only)
  • In low doses for rapid calming, particularly in institutionalized patients.

Route of Administration: Oral, Intramuscular (IM), Rectal, Intravenous (IV) (off-label)

Adults

• Nausea and Vomiting (Oral):
  • 5–10 mg 3 to 4 times daily
  • Max: 40 mg/day
• Nausea and Vomiting (IM or IV):
  • 5–10 mg every 3–4 hours as needed
  • Max: 40 mg/day
• Nausea and Vomiting (Rectal):
  • 25 mg twice daily (morning and evening)
• Psychosis/Schizophrenia (Oral):
  • Start with 5–10 mg 3 to 4 times daily
  • Maintenance: 15–60 mg/day in divided doses
  • Max: 100 mg/day in severe cases (rare)
• Vertigo:
  • 5 mg 3 to 4 times daily as needed

Elderly

• Start at lower doses (e.g., 2.5–5 mg once or twice daily)
• Increase cautiously due to higher sensitivity to extrapyramidal symptoms, sedation, and orthostatic hypotension

Pediatric Dosing

• Children >10 kg and >2 years:
  • 0.1 mg/kg/dose every 6–8 hours orally or rectally
  • Max single dose: 10 mg
  • Not recommended for children under 2 years or <10 kg due to risk of severe EPS

Renal or Hepatic Impairment

• Use with caution; start at the lowest effective dose
• Monitor closely for signs of CNS or anticholinergic toxicity

Prochlorperazine Maleate is a phenothiazine derivative that acts primarily as a dopamine D2 receptor antagonist in the chemoreceptor trigger zone (CTZ) of the brain, suppressing nausea and vomiting. At higher doses, it exerts antipsychotic activity by blocking dopamine receptors in the mesolimbic pathway, which reduces psychotic symptoms such as hallucinations and delusions. It also has weak anticholinergic and antihistaminic properties, contributing to its sedative effects and efficacy in vertigo. The antiemetic action is dose-independent, while antipsychotic effects are dose-dependent.

• Absorption:
  • Rapidly absorbed following oral and rectal administration
  • IM route yields reliable and consistent plasma levels
• Distribution:
  • Widely distributed in body tissues
  • Crosses blood-brain barrier and placenta
  • Highly protein-bound (90–99%)
• Metabolism:
  • Extensively metabolized in the liver, likely via CYP2D6 and CYP3A4 pathways
• Elimination:
  • Excreted mainly in urine and feces as metabolites
  • Minimal unchanged drug excreted
• Bioavailability:
  • Moderate for oral route due to first-pass metabolism
  • Higher with IM and rectal routes
• Onset of Action:
  • Oral: 30–60 minutes
  • IM: 10–20 minutes
  • Rectal: 30–60 minutes
• Half-Life:
  • Approximately 4–8 hours

• Pregnancy:
  • Previously FDA Category C
  • Use only if clearly needed; limited human data but potential risk of neonatal EPS and withdrawal symptoms with third-trimester use
  • Animal studies show potential teratogenicity at high doses
• Lactation:
  • Excreted into breast milk in small amounts
  • Potential for sedation, poor feeding, or EPS in infants
  • Avoid prolonged use during breastfeeding; monitor infant for adverse effects

• Primary Class: Antiemetic
• Subclass: Phenothiazine Derivative
• Secondary Class: Typical Antipsychotic (low-potency, first-generation)

• Known hypersensitivity to prochlorperazine or other phenothiazines
• Children <2 years of age or <10 kg body weight
• Presence of severe CNS depression or coma
• Bone marrow suppression
• Pheochromocytoma
• Narrow-angle glaucoma
• Severe hepatic dysfunction

• Extrapyramidal Symptoms (EPS): Risk of acute dystonia, pseudoparkinsonism, and akathisia; more frequent in younger patients and children
• Tardive Dyskinesia: Irreversible and potentially permanent; risk increases with duration and dose
• Neuroleptic Malignant Syndrome (NMS): Rare but life-threatening; signs include fever, rigidity, altered mental status, and autonomic instability
• Sedation and Hypotension: Monitor for excessive drowsiness and orthostatic hypotension, especially in elderly
• QT Prolongation: Risk of arrhythmias in predisposed patients or with QT-prolonging agents
• Hematologic Effects: Rare cases of agranulocytosis or leukopenia—monitor blood counts if long-term use
• Seizure Threshold Lowering: Use caution in epileptic patients
• Photosensitivity: May cause skin sensitivity to sunlight
• Use in Dementia-Related Psychosis: Increased risk of death in elderly patients treated with antipsychotic drugs

Common Side Effects:

• Neurological:
  • Drowsiness, dizziness, headache, extrapyramidal symptoms (tremor, rigidity, dystonia)
  • Restlessness (akathisia)
• Gastrointestinal:
  • Dry mouth, constipation, nausea
• Cardiovascular:
  • Hypotension, tachycardia, QT prolongation (rare)
• Ophthalmologic:
  • Blurred vision, visual disturbances

Serious and Rare Effects:

• Tardive dyskinesia (involuntary facial movements)
• Neuroleptic malignant syndrome
• Seizures
• Agranulocytosis or leukopenia
• Cholestatic jaundice
• Severe allergic reactions or anaphylaxis

Onset & Severity:

• Extrapyramidal symptoms can appear within hours to days of treatment
• Risk and severity are dose-dependent, especially with long-term or high-dose use

• CNS Depressants (alcohol, benzodiazepines, opioids): Additive sedation and respiratory depression
• QT-Prolonging Agents (e.g., amiodarone, macrolides): Increased risk of torsades de pointes
• Antihypertensives: Enhanced hypotensive effects
• Anticholinergics (e.g., atropine): Increased anticholinergic burden (dry mouth, constipation, confusion)
• Dopaminergic Agents (e.g., levodopa): Opposing effects; reduce therapeutic efficacy
• CYP450 Interactions:
  • CYP2D6 inhibitors may increase plasma levels
  • Use caution with strong CYP3A4 inhibitors or inducers

• Migraine Treatment: Still considered a valuable option in ED protocols for acute migraine with nausea
• Elderly Use Restrictions: Regulatory bodies emphasize minimizing use in elderly due to fall and EPS risk
• EMA & FDA Communications: Ongoing monitoring of extrapyramidal effects and QT prolongation has reinforced conservative dosing strategies
• Deprescribing Guidance: Recent geriatric guidelines recommend regular review and tapering when used long term in older adults

• Temperature: Store below 25°C (77°F)
• Light Protection: Store in original container, away from light
• Humidity: Keep in a dry place; protect from moisture
• Handling Precautions:
  • Do not freeze injectable forms
  • Shake suppositories gently before use (if applicable)
  • Keep out of reach of children
• Shelf Life: Check package insert; usually 2–3 years unopened
• Reconstitution: Not applicable (formulations are ready-to-use)