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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Phenothiazine [EPC]
Prochlorperazine is a potent phenothiazine derivative used primarily as an antiemetic for severe nausea and vomiting, as well as an antipsychotic for schizophrenia and non-psychotic anxiety. It functions by antagonizing dopamine receptors in the central nervous system.
Name
Prochlorperazine
Raw Name
PROCHLORPERAZINE MALEATE
Category
Phenothiazine [EPC]
Salt Form
Maleate
Drug Count
3
Variant Count
60
Last Verified
February 17, 2026
RxCUI
198365, 198159, 312635, 284254
UNII
I1T8O1JTL6, YHP6YLT61T
About Prochlorperazine
Prochlorperazine is a potent phenothiazine derivative used primarily as an antiemetic for severe nausea and vomiting, as well as an antipsychotic for schizophrenia and non-psychotic anxiety. It functions by antagonizing dopamine receptors in the central nervous system.
Detailed information about Prochlorperazine
This page is for informational purposes only and does not replace medical advice. Consult a qualified healthcare professional before using any medication containing Prochlorperazine.
Prochlorperazine is a first-generation antipsychotic and highly effective antiemetic (anti-nausea) medication belonging to the phenothiazine [EPC] class of drugs. Specifically, it is a propylamino derivative of phenothiazine. While initially developed in the mid-20th century for the treatment of psychiatric disorders, its profound effect on the chemoreceptor trigger zone (CTZ) in the brain has made it a cornerstone in the management of severe nausea and vomiting. The U.S. Food and Drug Administration (FDA) first approved prochlorperazine in the 1950s, and it remains a vital component of the clinical pharmacopeia for both acute and chronic symptom management.
In clinical practice, prochlorperazine is recognized for its versatility. It is frequently utilized in emergency departments for the rapid relief of migraine-associated nausea and is also indicated for the short-term treatment of generalized non-psychotic anxiety. As a member of the phenothiazine family, it shares structural similarities with drugs like chlorpromazine, though it is significantly more potent on a milligram-per-milligram basis, particularly in its antiemetic properties. Your healthcare provider may prescribe this medication under various brand names, most notably Compazine (though the brand name has been discontinued in some markets, the generic remains widely available).
Prochlorperazine exerts its therapeutic effects through the complex modulation of several neurotransmitter systems within the brain. Its primary mechanism of action involves the potent antagonism (blocking) of post-synaptic dopamine D2 receptors.
Beyond dopamine, prochlorperazine also possesses significant anticholinergic (blocking acetylcholine), antihistaminic (blocking histamine H1), and alpha-adrenergic blocking activity. These secondary interactions contribute to both the drug's therapeutic profile and its side effect spectrum, such as sedation and dry mouth.
The pharmacokinetics of prochlorperazine are characterized by significant inter-individual variability, which necessitates careful dosage titration by a healthcare professional.
Prochlorperazine is FDA-approved for several distinct clinical indications:
Prochlorperazine is available in several formulations to accommodate different clinical needs:
> Important: Only your healthcare provider can determine if Prochlorperazine is right for your specific condition. The choice of formulation and dosage will depend on the severity of your symptoms and your overall medical history.
Dosage for prochlorperazine must be strictly individualized based on the condition being treated and the patient's response. According to the FDA-approved labeling, the following are standard dosage ranges:
Prochlorperazine is not recommended for children under 2 years of age or children weighing less than 20 pounds (9 kg). In children over 2 years, dosing is based on weight:
Pediatric patients are at a significantly higher risk of developing extrapyramidal symptoms (movement disorders). Use should be limited to the shortest duration possible.
Specific dosage adjustments for renal impairment are not provided in the manufacturer's labeling; however, because the drug is primarily metabolized by the liver, significant renal impairment usually does not require major dose changes. Nevertheless, caution is advised as reduced excretion of metabolites could occur.
Prochlorperazine is extensively metabolized by the liver. Patients with hepatic insufficiency (liver disease) should be started on the lowest possible dose, as they are at an increased risk of drug accumulation and toxicity. Regular monitoring of liver function tests (LFTs) is recommended.
In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range (e.g., 2.5 mg to 5 mg once or twice daily). The elderly are more susceptible to side effects such as orthostatic hypotension (dizziness upon standing), sedation, and tardive dyskinesia.
If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and return to your regular dosing schedule. Do not double the dose to catch up, as this increases the risk of serious side effects.
Signs of a prochlorperazine overdose may include extreme drowsiness, irregular heartbeat, fainting, agitation, convulsions (seizures), and severe muscle stiffness or uncontrollable movements. If an overdose is suspected, contact a poison control center or seek emergency medical attention immediately. Treatment is primarily supportive, focusing on maintaining an open airway and monitoring cardiac function.
> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop taking this medication without medical guidance, as sudden discontinuation can lead to withdrawal symptoms.
Most patients taking prochlorperazine will experience some level of mild side effects, which often diminish as the body adjusts to the medication. Common effects include:
> Warning: Stop taking Prochlorperazine and call your doctor immediately if you experience any of the following serious symptoms:
Prolonged use of prochlorperazine increases the cumulative risk of Tardive Dyskinesia. The risk is highest in elderly patients, particularly women. Long-term use may also lead to persistent changes in glucose metabolism, potentially increasing the risk of developing Type 2 diabetes. Periodic blood glucose monitoring and movement disorder screenings (such as the AIMS test) are recommended for those on long-term therapy.
Dementia-Related Psychosis: The FDA has issued a Black Box Warning for all antipsychotic drugs, including prochlorperazine. Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Most deaths appeared to be either cardiovascular (e.g., heart failure, sudden death) or infectious (e.g., pneumonia) in nature. Prochlorperazine is not approved for the treatment of patients with dementia-related psychosis.
Report any unusual symptoms or changes in mood, movement, or physical health to your healthcare provider immediately. Regular follow-up appointments are essential to monitor for these potential complications.
Prochlorperazine is a potent medication that affects the central nervous system. Patients must be aware that it can impair mental and physical abilities. Activities requiring high levels of alertness, such as operating heavy machinery or driving, should be avoided until the patient’s response to the drug is well-established. Furthermore, prochlorperazine can interfere with the body's ability to regulate core temperature; patients should avoid extreme heat and stay well-hydrated to prevent heatstroke.
Increased Mortality in Elderly Patients with Dementia-Related Psychosis:
Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Analyses of seventeen placebo-controlled trials (modal duration of 10 weeks), largely in patients taking atypical antipsychotic drugs, revealed a risk of death in drug-treated patients of between 1.6 to 1.7 times the risk of death in placebo-treated patients. Although the causes of death were varied, most of the deaths appeared to be either cardiovascular or infectious in nature. Prochlorperazine is not approved for the treatment of patients with dementia-related psychosis.
Healthcare providers will typically require the following monitoring while a patient is on prochlorperazine:
Due to the high incidence of somnolence (drowsiness) and blurred vision, patients should not drive or operate complex machinery until they are certain the medication does not impair their coordination or judgment. The sedative effects are often most pronounced during the first week of treatment or following a dose increase.
Alcohol must be strictly avoided while taking prochlorperazine. Alcohol can dangerously increase the sedative effects of the drug, leading to severe respiratory depression, extreme dizziness, and an increased risk of accidental injury or overdose.
Prochlorperazine should not be stopped abruptly, especially after long-term use. Sudden discontinuation can cause withdrawal symptoms, including nausea, vomiting, dizziness, and tremors. It may also cause a rapid return of the symptoms being treated. Your doctor will provide a tapering schedule to gradually reduce the dose.
> Important: Discuss all your medical conditions, especially heart disease, liver problems, or a history of glaucoma, with your healthcare provider before starting Prochlorperazine.
Prochlorperazine may interfere with certain laboratory tests:
For each major interaction, the clinical consequence is usually an increase in side effects (toxicity) or a decrease in the effectiveness of either prochlorperazine or the co-administered drug. Management strategies often involve dose adjustment or choosing an alternative therapy.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, including over-the-counter cold or allergy medicines.
Prochlorperazine must NEVER be used in the following circumstances:
Conditions requiring a careful risk-benefit analysis by a physician include:
Patients who have experienced a severe reaction (such as jaundice, blood cell changes, or severe rashes) to other phenothiazines are at a high risk of a similar reaction to prochlorperazine. Always inform your doctor if you have had a negative reaction to medications like promethazine (Phenergan) or fluphenazine in the past.
> Important: Your healthcare provider will evaluate your complete medical history, including any history of 'fainting spells' or irregular heartbeats, before prescribing Prochlorperazine.
Prochlorperazine is classified as FDA Pregnancy Category C. There are no adequate and well-controlled studies in pregnant women. Animal studies have suggested potential harm to the fetus.
It is not known whether prochlorperazine is excreted in human milk. However, because many drugs are excreted in breast milk and because of the potential for serious adverse reactions in nursing infants (such as extreme sedation or movement disorders), a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
As previously noted, prochlorperazine is contraindicated in children under 2 years of age. In older children, it should be used with extreme caution and only for severe nausea or vomiting that has not responded to other measures. Children are much more likely than adults to develop acute dystonic reactions (painful muscle spasms of the neck or back). It should not be used in children with symptoms suggestive of Reye's Syndrome, as the drug's side effects may mask the diagnosis of this serious condition.
Clinical studies of prochlorperazine did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. However, geriatric patients are known to have a higher incidence of:
While the liver is the primary metabolic organ, the kidneys excrete the metabolites. In patients with severe renal failure, these metabolites may accumulate. While specific GFR-based dosing is not standardized, clinicians typically monitor these patients closely for increased sedation or neurological side effects.
In patients with hepatic impairment, the clearance of prochlorperazine is reduced. This can lead to a prolonged half-life and increased risk of toxicity. For patients with a Child-Pugh score indicating moderate to severe liver disease, starting doses should be reduced by at least 50%, and the patient should be monitored for signs of jaundice or worsening encephalopathy.
> Important: Special populations require individualized medical assessment and more frequent monitoring of blood work and vital signs.
Prochlorperazine is a dopamine D2 receptor antagonist. Its primary therapeutic effects are mediated through the blockade of D2 receptors in specific pathways of the brain:
Additionally, prochlorperazine acts as an antagonist at:
The onset of action for oral prochlorperazine is typically 30 to 40 minutes. For rectal suppositories, it is approximately 60 minutes, and for intramuscular injection, it is 10 to 20 minutes. The duration of effect generally lasts between 3 to 4 hours, though the antipsychotic effects may take several weeks of consistent dosing to reach full therapeutic potential. Tolerance to the sedative effects often develops over time, but tolerance to the antipsychotic or antiemetic effects is less common.
| Parameter | Value |
|---|---|
| Bioavailability | ~12-16% (due to high first-pass metabolism) |
| Protein Binding | >90% (primarily to albumin) |
| Half-life | 3 to 5 hours (plasma terminal half-life) |
| Tmax | 1.5 to 4 hours (Oral) |
| Metabolism | Hepatic (CYP2D6, Sulfoxidation) |
| Excretion | Fecal (Major), Renal (<5% unchanged) |
Prochlorperazine is classified as a 'typical' or first-generation antipsychotic (FGA). Within this group, it belongs to the piperazine subclass of phenothiazines. Other medications in the phenothiazine class include chlorpromazine (Thorazine), fluphenazine (Prolixin), and promethazine (Phenergan). Compared to chlorpromazine, prochlorperazine has higher antiemetic potency and a lower tendency to cause profound sedation, but a higher risk of extrapyramidal symptoms.
Medications containing this ingredient
Common questions about Prochlorperazine
Prochlorperazine is primarily used to control severe nausea and vomiting caused by various conditions, such as surgery, radiation therapy, or migraines. It is also FDA-approved for the short-term treatment of non-psychotic anxiety in patients who haven't responded to other therapies. Additionally, it is used as an antipsychotic medication to manage symptoms of schizophrenia. Because it is a potent medication, it is usually reserved for cases where other treatments have failed. Your doctor will determine the appropriate use based on your specific symptoms and medical history.
The most common side effects include drowsiness, dizziness, dry mouth, and blurred vision. Some patients may also experience constipation or a 'jittery' feeling known as akathisia. These effects are often most noticeable when you first start the medication and may improve as your body adjusts. However, if you experience muscle stiffness or uncontrollable movements, you should contact your doctor immediately. It is important to stay hydrated and avoid sudden movements to minimize dizziness.
No, you should strictly avoid alcohol while taking prochlorperazine. Alcohol can significantly increase the sedative effects of the drug, leading to extreme drowsiness, impaired coordination, and a higher risk of accidents. Combining the two can also lead to dangerous respiratory depression, where your breathing becomes too shallow or slow. Furthermore, alcohol increases the risk of a sudden drop in blood pressure when you stand up. Always consult your healthcare provider before consuming any substance that affects the central nervous system.
Prochlorperazine is generally not recommended during pregnancy unless the benefits clearly outweigh the potential risks to the fetus. It is classified as Category C, meaning animal studies have shown risks, but human data is limited. Use during the third trimester can lead to withdrawal symptoms or movement disorders in the newborn baby after birth. If you are pregnant or planning to become pregnant, discuss alternative treatments for nausea with your doctor. They will help you weigh the risks of the medication against the risks of untreated severe vomiting.
The time it takes for prochlorperazine to work depends on the form you are taking. Oral tablets typically begin to work within 30 to 40 minutes, while rectal suppositories may take up to an hour. If you receive an intramuscular injection, you may feel relief in as little as 10 to 20 minutes. For psychiatric conditions like schizophrenia, it may take several weeks of consistent use to see the full therapeutic benefits. Always follow the schedule prescribed by your doctor for the best results.
You should not stop taking prochlorperazine suddenly, especially if you have been taking it for a long period or at a high dose. Abruptly stopping the medication can cause withdrawal symptoms such as nausea, vomiting, dizziness, and tremors. It can also lead to a rapid recurrence of the psychiatric or anxiety symptoms being treated. Your doctor will typically provide a tapering schedule to slowly reduce your dose over time. This gradual reduction helps your brain and body adjust safely.
If you miss a dose, take it as soon as you remember. However, if it is nearly time for your next scheduled dose, skip the missed one and continue with your regular routine. Never take two doses at once to make up for a missed one, as this significantly increases the risk of serious side effects like muscle spasms or extreme sedation. If you frequently forget doses, consider using a pill organizer or setting an alarm. Consistency is key to the effectiveness of this medication.
Weight gain is a known potential side effect of prochlorperazine, though it is generally less common than with some other antipsychotic medications. The drug can cause metabolic changes or an increase in appetite in some patients. If you are taking this medication long-term, it is a good idea to monitor your weight and discuss any significant changes with your doctor. They may recommend dietary adjustments or regular exercise to help manage this side effect. In some cases, blood sugar monitoring may also be necessary.
Prochlorperazine has many potential drug interactions, so it is vital to tell your doctor about everything you take. It can interact poorly with other CNS depressants, blood pressure medications, and drugs that affect heart rhythm. Taking it with metoclopramide (Reglan) is particularly risky due to the increased chance of movement disorders. Even over-the-counter supplements like St. John's Wort or Kava can interfere with how the drug works. Your pharmacist can provide a comprehensive screening for interactions based on your current medication list.
Yes, prochlorperazine is widely available as a generic medication in several forms, including tablets and injectable solutions. Generic versions are typically much more affordable than brand-name versions and contain the same active ingredient with the same efficacy and safety profile. The brand name Compazine is no longer widely marketed in many regions, so most patients receive the generic version. Check with your insurance provider or pharmacist to ensure you are getting the most cost-effective option available to you.