Compazine (prochlorperazine) is a prescription phenothiazine antipsychotic medication with potent antiemetic and antipsychotic properties. It is primarily indicated for the management of severe nausea and vomiting, as well as for the control of manifestations of psychotic disorders. Its mechanism of action involves blocking dopamine receptors in the chemoreceptor trigger zone (CTZ) of the brain and in the mesolimbic system, which underlies both its antiemetic and antipsychotic efficacy. Healthcare professionals prescribe Compazine for its rapid onset and established therapeutic profile in appropriate clinical scenarios, though its use requires careful patient selection and monitoring due to potential neurological and cardiovascular effects.

Features

• Active ingredient: Prochlorperazine
• Available formulations: Tablets (5 mg, 10 mg), extended-release capsules (10 mg, 15 mg, 30 mg), injection (5 mg/mL), suppositories (2.5 mg, 5 mg, 25 mg)
• Pharmacologic class: Phenothiazine derivative, dopamine antagonist
• Half-life: Approximately 6–8 hours (oral), 3–5 hours (IV/IM)
• Onset of action: 30–40 minutes (oral), 10–20 minutes (IM), 3–5 minutes (IV)
• Metabolism: Hepatic, primarily via CYP2D6
• Excretion: Urine and feces

Benefits

• Provides rapid and effective control of severe nausea and vomiting, including that associated with surgery, cancer chemotherapy, or radiation therapy
• Offers management of acute psychotic agitation and manifestations of schizophrenia and other psychotic disorders
• Available in multiple formulations allowing for flexible administration routes based on clinical need and patient condition
• Demonstrates reliable efficacy with a well-characterized pharmacokinetic profile in appropriate patient populations
• Can be used as adjunctive therapy in generalized non-psychotic anxiety when other treatments have been ineffective
• Established clinical usage with extensive documentation in medical literature

Common use

Compazine is commonly prescribed for the management of severe nausea and vomiting in various clinical contexts, including postoperative recovery, chemotherapy-induced nausea, and radiation therapy side effects. In psychiatric practice, it is used to control manifestations of psychotic disorders such as schizophrenia, particularly when managing acute agitation. It may also be employed as adjunctive therapy in generalized non-psychotic anxiety that has not responded to first-line treatments. The medication is typically used for short-term management of acute symptoms rather than as a first-line maintenance therapy for chronic conditions.

Dosage and direction

Adults (Nausea and Vomiting):

• Tablets: 5–10 mg 3–4 times daily
• Extended-release capsules: 10 mg every 12 hours or 15 mg once daily
• IM injection: 5–10 mg every 3–4 hours (maximum 40 mg/day)
• IV administration: 2.5–10 mg at a rate not exceeding 5 mg/minute

Adults (Psychotic Disorders):

• Initial: 5–10 mg 3–4 times daily
• Maintenance: May be increased gradually to 50–75 mg daily in divided doses
• Severe cases: Up to 100–150 mg daily may be required

Elderly/Debilitated Patients: Lower initial doses (2.5–5 mg 1–3 times daily) with gradual titration based on response and tolerance.

Administration with food or milk may minimize gastrointestinal upset. Tablets should be swallowed whole; do not crush or chew extended-release formulations. IM injections should be administered deep into large muscle mass. IV administration requires careful monitoring of blood pressure and should be diluted and administered slowly.

Precautions

Compazine carries a Black Box Warning regarding increased mortality in elderly patients with dementia-related psychosis. Use requires careful risk-benefit assessment in this population. Neurological precautions include monitoring for extrapyramidal symptoms (EPS), tardive dyskinesia, and neuroleptic malignant syndrome (NMS). Cardiovascular monitoring is essential due to potential QT prolongation and orthostatic hypotension. Hepatic impairment requires dosage adjustment and close monitoring. Patients should be cautioned about operating machinery or driving until response is established. Temperature regulation may be impaired; avoid excessive heat exposure. Periodic eye examinations are recommended due to potential corneal and lenticular changes. Blood dyscrasias, including agranulocytosis, have been reported; monitor complete blood counts regularly.

Contraindications

Compazine is contraindicated in patients with known hypersensitivity to prochlorperazine or other phenothiazines. Additional contraindications include:

• Comatose or severely depressed states due to CNS depressants
• Bone marrow depression
• Significant hepatic impairment
• Pediatric patients under 2 years of age or weighing less than 9 kg
• Concomitant use with other QT-prolonging agents in patients with known QT prolongation
• History of neuroleptic malignant syndrome
• Patients with suspected or established subcortical brain damage

Possible side effect

Common (≥1%):

• Drowsiness, dizziness
• Dry mouth, blurred vision
• Extrapyramidal symptoms (dystonia, akathisia, parkinsonism)
• Orthostatic hypotension
• Constipation

Less Common (<1%):

• Tardive dyskinesia
• Neuroleptic malignant syndrome
• QT prolongation, tachycardia
• Blood dyscrasias (leukopenia, agranulocytosis)
• Hyperprolactinemia
• Photosensitivity reactions
• Jaundice, hepatic dysfunction
• Seizures
• Temperature dysregulation

Rare:

• Ocular changes (corneal and lenticular deposits)
• Skin pigmentation changes
• Cardiac arrhythmias

Drug interaction

Compazine demonstrates significant drug interactions requiring careful management:

• CNS Depressants: Enhanced sedation with alcohol, opioids, benzodiazepines, and other sedatives
• Anticholinergics: Increased anticholinergic effects and potential for hyperthermia
• QT-Prolonging Agents: Additive risk with antiarrhythmics, macrolides, fluoroquinolones
• Antihypertensives: Potentiated hypotension
• Dopamine Agonists: Antagonized effects of levodopa, bromocriptine
• CYP2D6 Inhibitors: Increased prochlorperazine levels with paroxetine, fluoxetine, quinidine
• Lithium: Increased risk of neurotoxicity and EPS
• Metoclopramide: Additive EPS risk

Missed dose

If a dose is missed, take it as soon as remembered unless it is nearly time for the next scheduled dose. Do not double the dose to make up for a missed administration. For patients on multiple daily dosing, if remembered within 2 hours of the scheduled time, take the missed dose and resume regular schedule. If more than 2 hours have passed, skip the missed dose and continue with the next scheduled dose. For once-daily regimens, take the missed dose if remembered within 6 hours; otherwise, skip and resume next day. Do not take extra medication to compensate for a missed dose.

Overdose

Overdose symptoms include severe CNS depression (coma, respiratory depression), extrapyramidal symptoms, hypotension, agitation, restlessness, convulsions, fever, and cardiac arrhythmias. Management involves immediate medical attention with supportive care: maintain airway, assist ventilation if needed, and monitor cardiac function. Gastric lavage may be considered if presented early. Activated charcoal may be administered. There is no specific antidote; treatment is symptomatic and supportive. Cardiovascular monitoring for QT prolongation and arrhythmias is essential. Hypotension should be managed with IV fluids and vasopressors if necessary. Avoid epinephrine due to potential paradoxical hypotension. Extrapyramidal symptoms may require anticholinergic agents. Dialysis is not effective due to high protein binding.

Storage

Store at controlled room temperature (20–25°C or 68–77°F). Protect from light and moisture. Keep in original container with tight closure. Do not freeze liquid formulations. Keep all medications out of reach of children and pets. Do not store in bathroom due to humidity variations. Discard any medication that has changed color or shows signs of deterioration. Unused medication should be properly disposed of according to local regulations or through medication take-back programs.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Compazine is a prescription medication that should only be used under the supervision of a qualified healthcare professional. The prescribing physician will determine appropriate dosage and duration based on individual patient factors. Patients should not adjust dosage or discontinue medication without medical consultation. This summary does not include all possible information about this medication. Always consult with a healthcare provider for complete information about prescription medications and their appropriate use.

Reviews

Clinical experience with Compazine demonstrates effective antiemetic properties in approximately 70-80% of patients with severe nausea and vomiting. Psychiatric applications show significant improvement in acute psychotic symptoms in appropriate patient populations. Many clinicians note the medication’s rapid onset of action as particularly valuable in emergency settings. However, reviews consistently emphasize the importance of careful patient selection and monitoring due to the significant side effect profile, particularly regarding extrapyramidal symptoms and cardiovascular effects. Elderly patients require particularly cautious use due to increased sensitivity to side effects. The multiple available formulations are frequently cited as advantageous for tailoring therapy to specific clinical situations.