Compazine (prochlorperazine) is a prescription phenothiazine antipsychotic medication primarily indicated for the management of severe nausea and vomiting, as well as for the treatment of schizophrenia and non-psychotic anxiety. It functions by blocking dopamine receptors in the brain, which helps to reduce psychotic symptoms and suppress the chemoreceptor trigger zone (CTZ) responsible for initiating vomiting. This medication is available in multiple formulations, including tablets, suppositories, and injectable solutions, allowing for tailored treatment approaches based on clinical need and patient tolerance. Due to its potent effects, it is reserved for cases where other antiemetics or less potent antipsychotics have proven ineffective or are unsuitable.

Features

• Active ingredient: Prochlorperazine
• Available formulations: Oral tablets (5 mg, 10 mg), rectal suppositories (25 mg), injectable solution (5 mg/mL)
• Mechanism of action: Dopamine D2 receptor antagonist
• Onset of action: Oral—30–40 minutes; IM—10–20 minutes; Rectal—60 minutes
• Duration of effect: 3–4 hours (oral/IM), 10–12 hours (suppository)
• Prescription-only medication

Benefits

• Provides rapid and effective control of severe, treatment-resistant nausea and vomiting
• Reduces agitation, hallucinations, and delusions in psychotic disorders such as schizophrenia
• Offers flexible administration routes for patients unable to tolerate oral intake
• Can be used short-term for severe anxiety with accompanying nausea or vomiting
• Helps restore functional capacity in acute psychotic episodes
• May reduce the need for hospitalization in adequately managed cases

Common use

Compazine is commonly prescribed for the management of severe nausea and vomiting associated with conditions such as surgery, chemotherapy, radiation therapy, or acute gastroenteritis. In psychiatric practice, it is used to control symptoms of schizophrenia, including thought disorder, agitation, and paranoid ideation. It is also occasionally used for the short-term treatment of severe, disabling anxiety that has not responded to other interventions. Off-label uses may include the treatment of migraine-associated nausea and vomiting, though this is not an FDA-approved indication.

Dosage and direction

Dosage must be individualized based on indication, severity of symptoms, patient response, and formulation used.

For severe nausea/vomiting:

• Adults: Oral—5–10 mg 3–4 times daily; IM—5–10 mg every 3–4 hours (max 40 mg/day); Rectal—25 mg twice daily.
• Children (≥2 years, ≥20 lb): Oral—0.4 mg/kg/24 hr divided in 3–4 doses; IM—0.1–0.15 mg/kg/dose every 3–4 hours.

For psychosis:

• Adults: Oral—5–10 mg 3–4 times daily (max 150 mg/day); IM—10–20 mg every 2–4 hours (max 40 mg/day).
• Elderly/debilitated patients: Lower initial doses (e.g., 5 mg 1–2 times daily) with gradual titration.

Administer with food or milk to minimize gastrointestinal upset. Avoid abrupt discontinuation; taper gradually under medical supervision.

Precautions

Use with caution in patients with cardiovascular disease, glaucoma, seizure disorders, or Parkinson’s disease. May impair mental or physical abilities required for hazardous tasks (e.g., driving). Avoid alcohol and other CNS depressants. Periodic monitoring of CBC, liver function, and ophthalmologic exams recommended during prolonged therapy. Risk of neuroleptic malignant syndrome (NMS) and tardive dyskinesia (TD) exists, especially with long-term use. Elderly patients with dementia-related psychosis are at increased risk of death. Use during pregnancy only if potential benefit justifies potential risk to the fetus.

Contraindications

Hypersensitivity to prochlorperazine or other phenothiazines; comatose or severely depressed states; bone marrow suppression; pediatric patients under 2 years or weighing less than 20 lb; concomitant use of large doses of CNS depressants. Not recommended in patients with suspected or established subcortical brain damage.

Possible side effect

Common: Drowsiness, dizziness, dry mouth, blurred vision, constipation, hypotension. Less common: Extrapyramidal symptoms (e.g., dystonia, akathisia, parkinsonism), tardive dyskinesia, neuroleptic malignant syndrome, leukopenia, agranulocytosis, jaundice. Rare: Photosensitivity, skin reactions, seizures, pigmentary retinopathy.

Drug interaction

Potentiates effects of CNS depressants (alcohol, opioids, sedatives). May reduce effects of levodopa and other dopamine agonists. Concurrent use with antihypertensives may increase risk of hypotension. QT-prolonging agents may increase risk of arrhythmias. Anticholinergics may increase risk of heat stroke and paralytic ileus.

Missed dose

If a dose is missed, take it as soon as remembered unless it is almost time for the next dose. Do not double the dose to make up for a missed one. Resume regular dosing schedule.

Overdose

Symptoms may include severe drowsiness, coma, hypotension, tachycardia, extrapyramidal symptoms, agitation, restlessness, convulsions. ECG may show prolonged QT interval. Treatment is supportive and symptomatic; there is no specific antidote. Gastric lavage and activated charcoal may be considered if ingestion is recent. Avoid epinephrine in hypotensive crisis due to risk of paradoxical further decrease in blood pressure.

Storage

Store at room temperature (15–30°C or 59–86°F) in a tight, light-resistant container. Keep away from moisture and heat. Do not freeze. Keep out of reach of children and pets.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before starting, changing, or discontinuing any medication. Do not use this information to self-diagnose or self-treat.

Reviews

Clinical studies and patient reports indicate that Compazine is highly effective for severe nausea and vomiting, with many patients experiencing rapid symptom relief. Psychiatric use shows significant improvement in positive symptoms of schizophrenia, though extrapyramidal side effects are frequently reported. Many clinicians emphasize the importance of dose individualization and close monitoring to maximize benefits and minimize adverse effects.