Drug Guide
Prochlorperazine Maleate
Classification
Therapeutic: Antiemetic, Antipsychotic
Pharmacological: Phenothiazine derivative
FDA Approved Indications
- Nausea and vomiting
- Psychotic disorders (e.g., schizophrenia)
Mechanism of Action
Blocks dopamine receptors in the brain, particularly in the chemoreceptor trigger zone (CTZ), reducing nausea and psychotic symptoms.
Dosage and Administration
Adult: Typically 5-10 mg three to four times daily, adjusted based on response.
Pediatric: Dose varies; generally 0.15 mg/kg/day divided into 3-4 doses, not to exceed 40 mg/day.
Geriatric: Start at lower doses due to increased sensitivity; monitor closely.
Renal Impairment: Use with caution; dose adjustments may be necessary.
Hepatic Impairment: Use with caution; monitor for increased sedation or EPS.
Pharmacokinetics
Absorption: Well absorbed orally.
Distribution: Widely distributed, crosses the blood-brain barrier.
Metabolism: Primarily hepatic via the cytochrome P450 system.
Excretion: Renal and biliary excretion.
Half Life: Approximately 10-19 hours.
Contraindications
- Comatose states
- Bone marrow suppression
- Hypersensitivity to phenothiazines
Precautions
- Sedation, EPS, anticholinergic effects, hypotension
- Use cautiously in elderly, Parkinson's disease, cardiac disorders, and in those with a history of seizure disorder
Adverse Reactions - Common
- Drowsiness, dizziness, dry mouth (Common)
- Extrapyramidal symptoms (EPS) (Common)
- Dizziness, orthostatic hypotension (Common)
Adverse Reactions - Serious
- Tardive dyskinesia (Serious and potentially irreversible)
- Neuroleptic malignant syndrome (NMS) (Rare)
- QT prolongation and arrhythmias (Rare)
Drug-Drug Interactions
- Other CNS depressants, antihypertensives, drugs that prolong QT interval
Drug-Food Interactions
- Alcohol potentiates sedative effects
Drug-Herb Interactions
- St. John's Wort may increase risk of CNS side effects
Nursing Implications
Assessment: Monitor for EPS, sedation, blood pressure, baseline ECG in high-risk patients.
Diagnoses:
- Risk for injury due to sedation or EPS
Implementation: Administer with food to decrease gastrointestinal irritation; monitor for signs of EPS and NMS.
Evaluation: Assess effectiveness in controlling nausea and psychosis; monitor for adverse effects.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report any involuntary movements, fever, muscle rigidity.
- Avoid alcohol and CNS depressants.
- Caution when operating machinery due to sedation.
Special Considerations
Black Box Warnings:
- Increased risk of death in elderly patients with dementia-related psychosis
Genetic Factors: Slow metabolizers may have increased plasma levels leading to enhanced effects and side effects.
Lab Test Interference: May cause false-positive in some diagnostic tests of catecholamine levels.
Overdose Management
Signs/Symptoms: Sedation, hypotension, EPS, coma.
Treatment: Supportive care, activated charcoal if recent ingestion, monitor vital signs, manage symptoms; possibly use diphenhydramine for EPS.
Storage and Handling
Storage: Store at room temperature, away from moisture and light.
Stability: Stable for 2-3 years if stored properly.