Compazine (prochlorperazine) is a prescription phenothiazine antipsychotic and antiemetic agent used for the management of severe nausea and vomiting, as well as for the control of manifestations of psychotic disorders. It works 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 various formulations, including tablets, suppositories, and injectable solutions, allowing for flexible administration based on clinical need and patient condition. It is typically reserved for cases where other, less potent antiemetics have proven ineffective, due to its potential for significant side effects.

Features

• Active ingredient: Prochlorperazine
• Available in 5 mg and 10 mg tablets, 25 mg suppositories, and injectable solution (5 mg/mL)
• Belongs to the phenothiazine class of antipsychotics
• Functions as a dopamine antagonist
• Multiple administration routes: oral, rectal, intramuscular
• Requires a prescription

Benefits

• Provides rapid and effective control of severe nausea and vomiting, including that induced by chemotherapy, surgery, or vertigo
• Helps manage acute psychotic episodes, reducing agitation, hallucinations, and delusions
• Offers flexible dosing options to accommodate patient needs and clinical scenarios
• Can be administered when oral intake is not feasible (e.g., via suppository or injection)
• May reduce the need for hospitalization in certain acute psychiatric or severe emesis cases
• Supports overall patient comfort and stability during medically challenging treatments or episodes

Common use

Compazine is commonly prescribed for the management of severe nausea and vomiting not responsive to conventional treatments. This includes nausea associated with cancer chemotherapy, radiation therapy, postoperative recovery, and severe vertigo. In psychiatric practice, it is used for the short-term treatment of generalized non-agitated anxiety and for the control of severe agitation, hyperactivity, or manifestations of psychotic disorders such as schizophrenia. Its use is generally limited to acute situations rather than chronic management due to the risk of extrapyramidal symptoms and other adverse effects.

Dosage and direction

Dosage must be individualized based on the condition being treated, severity of symptoms, patient response, and route of administration. For severe nausea and vomiting in adults: oral tablets—usually 5 to 10 mg three or four times daily; suppositories—25 mg twice daily; IM injection—5 to 10 mg every three to four hours as needed, not to exceed 40 mg per day. For psychiatric disorders: oral tablets—usually 5 to 10 mg three or four times daily; IM injection—10 to 20 mg every two to four hours until controlled, usually not exceeding 3 to 4 doses. Elderly or debilitated patients typically require lower doses. Always follow the specific instructions provided by the prescribing physician.

Precautions

Patients should be monitored closely for neurological side effects, particularly extrapyramidal symptoms (EPS) such as dystonia, akathisia, parkinsonism, and tardive dyskinesia. Use with caution in patients with cardiovascular disease, glaucoma, prostate hypertrophy, or a history of seizures. May cause drowsiness or dizziness; patients should avoid driving or operating machinery until they know how the medication affects them. Avoid abrupt discontinuation after prolonged use. Not recommended for use in children under 2 years of age or weighing less than 9 kg. May cause orthostatic hypotension; advise patients to rise slowly from sitting or lying positions.

Contraindications

Compazine is contraindicated in patients with known hypersensitivity to prochlorperazine or other phenothiazines. Should not be used in comatose or severely depressed states, or in patients with bone marrow suppression. Contraindicated in patients with suspected subcortical brain damage, with or without hypothalamic damage, as there is an increased risk of sudden death in this population. Avoid use in patients with severe hepatic or renal impairment. Not recommended for use in pediatric surgery or in children with acute illnesses or dehydration due to increased risk of extrapyramidal symptoms.

Possible side effect

Common side effects may include drowsiness, dizziness, blurred vision, dry mouth, constipation, and orthostatic hypotension. Extrapyramidal symptoms (EPS) such as restlessness, muscle spasms, tremors, and shuffling walk may occur. Less commonly, neuroleptic malignant syndrome (NMS)—characterized by fever, muscle rigidity, altered mental status, and autonomic instability—may develop and constitutes a medical emergency. Tardive dyskinesia, characterized by involuntary movements of the tongue, face, and jaw, may occur with prolonged use and can be irreversible. Other potential side effects include photosensitivity, blood dyscrasias, and jaundice.

Drug interaction

Compazine may potentiate the effects of CNS depressants such as alcohol, barbiturates, and opioids. Concurrent use with other drugs that prolong the QT interval (e.g., certain antiarrhythmics, antibiotics) may increase the risk of serious cardiac arrhythmias. May antagonize the effects of levodopa and other dopamine agonists. Use with epinephrine may result in paradoxical hypotension. Antacids and antidiarrheals may decrease absorption of oral prochlorperazine. May enhance the hypotensive effects of antihypertensive medications. Caution is advised when using with other drugs that cause extrapyramidal symptoms.

Missed dose

If a dose is missed, it should be taken as soon as remembered unless it is almost time for the next scheduled dose. In that case, skip the missed dose and resume the regular dosing schedule. Do not double the dose to make up for a missed one. If multiple doses are missed or if uncertainty exists about how to proceed, contact the prescribing healthcare provider for guidance. Consistent dosing is important for maintaining therapeutic effect, particularly in the management of psychotic disorders.

Overdose

Symptoms of overdose may include severe drowsiness, deep sleep, coma, agitation, restlessness, convulsions, fever, hypotension, and extrapyramidal symptoms. Cardiac arrhythmias and QT prolongation may occur. In severe cases, neuroleptic malignant syndrome (NMS) may develop. Treatment is supportive and symptomatic; there is no specific antidote. Gastric lavage may be considered if ingestion was recent. Maintain airway and assist ventilation if necessary. ECG monitoring is recommended. Management of hypotension may require IV fluids and vasopressors. Avoid use of epinephrine. Extrapyramidal symptoms may be treated with diphenhydramine or benztropine.

Storage

Store at room temperature (15–30°C or 59–86°F) away from light, moisture, and heat. Keep tablets and suppositories in their original container, tightly closed. Do not freeze the injectable form. Keep out of reach of children and pets. Do not use beyond the expiration date printed on the packaging. Properly discard any unused medication according to specific local guidelines or through a medication take-back program. Do not flush medications down the toilet or pour into a drain unless instructed to do so.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting, changing, or stopping any medication. The prescribing physician should be aware of the patient’s full medical history, current medications, and specific health conditions. This summary may not include all possible information, risks, or uses for this medication. Only a healthcare provider can determine the appropriate treatment for an individual patient.

Reviews

Clinical experience and patient reports generally indicate that Compazine is highly effective for its indicated uses, particularly in controlling severe nausea and vomiting and managing acute psychotic agitation. Many healthcare providers note its rapid onset of action, especially with injectable administration. However, reviews frequently mention the significant side effect profile, particularly extrapyramidal symptoms, which can be distressing for patients. It is often described as a valuable tool in specific clinical scenarios but one that requires careful patient selection and monitoring. Long-term use is generally discouraged due to the risk of tardive dyskinesia and other chronic side effects.