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Compazine vs Thorazine

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Compazine Information

Thorazine Information


Dosage Information

Side Effects

Warnings and Precautions


Market Information


For patients with psychotic disorders or severe nausea and vomiting, certain drugs that alter the concentrations of compounds in the brain called neurotransmitters can help manage symptoms. Compazine (prochlorperazine) and Thorazine (chlorpromazine) are two such medications frequently used to treat these conditions. Both belong to a class of drugs known as phenothiazines which work by blocking dopamine receptors in the brain. Compazine primarily affects areas of the brain associated with emesis (vomiting), making it an effective anti-emetic medication often used post-surgery or for patients undergoing chemotherapy. On the other hand, Thorazine has a broader effect on various parts of the brain and is more commonly used as an antipsychotic drug for managing disorders like schizophrenia, manic phase of bipolar disorder, agitation and confusion.

Compazine vs Thorazine Side By Side

Brand NameCompazineThorazine
ContraindicationsShould not be taken with large amounts of alcohol or substances with CNS depressant properties such as sedatives.Should not be taken with large amounts of alcohol or substances with CNS depressant properties such as sedatives.
CostFor brand name, around $100 for 60 tablets of 5 mg. For generic prochlorperazine, costs range from $0.15 to $1.00 per day.For brand name, about $200 for 30 tablets of 50 mg. For generic chlorpromazine, costs start from around $0.20/day up to about $.90/day.
Generic NameProchlorperazineChlorpromazine
Most Serious Side EffectExtreme restlessness or anxiety, signs of an allergic reaction, vision changes, unusual heartbeats, symptoms of low sodium levels, severe nervous system reactions, serotonin syndrome.Allergic reactions, neuroleptic malignant syndrome, tardive dyskinesia, unusual thoughts or behavior, changes in vision, rapid heartbeat patterns, signs indicative of mania.
Severe Drug InteractionsNot specified in the provided text, but typically includes interactions with other CNS depressants, medications that prolong the QT interval, and certain anticholinergic drugs.Not specified in the provided text, but typically includes interactions with other CNS depressants, medications that can induce arrhythmias, and certain anticholinergic drugs.
Typical DoseOral dosages range from 5–10 mg, taken 3-4 times per day for adults. For children aged between two and twelve years old, the recommended starting dose is 2.5 mg given twice or three times daily.Treatment typically begins with a dosage of 25-50 mg, three to four times per day. The dose can then be increased to 400mg/day or more, based on individual response and tolerance.

What is Compazine?

Prochlorperazine (the generic name for Compazine) was one of the first drugs in a class known as phenothiazine antipsychotics, which marked significant progress from previous classes of psychiatric medications. It was first approved by the FDA in 1956. Compazine works primarily by blocking dopamine receptors in the brain and is prescribed for the treatment of severe nausea and vomiting, as well as psychotic disorders such as schizophrenia. This drug has a selective influence on dopamine with only minor effects on other neurotransmitters like serotonin.

Chlorpromazine (known more commonly by its brand name Thorazine), also belongs to this family of phenothiazines but unlike Prochlorperazine, it impacts several different types of neurotransmitter pathways including those involving dopamine, histamine, norepinephrine (noradrenaline), acetylcholine and even serotonin. As a result, its side effect profile may be more extensive than that seen with Prochlorperazine due to these broader actions within the nervous system.

What conditions is Compazine approved to treat?

Compazine has been approved for the treatment of various conditions including:

  • Severe nausea and vomiting
  • Psychotic disorders such as schizophrenia
  • Non-psychotic anxiety

Meanwhile, Thorazine is used primarily for:

  • Manic phase of bipolar disorder
  • Treatment-resistant depression (when used in combination with other drugs)
  • Nausea and vomiting
  • Acute intermittent porphyria.

How does Compazine help with these illnesses?

Compazine helps to manage symptoms of various mental and emotional conditions, including schizophrenia and anxiety, by reducing the amount of dopamine available in the synapses of the brain. It does this by blocking it from binding to its receptors on neurons, thus maintaining lower levels for longer periods. Dopamine is a neurotransmitter that acts as a messenger in the brain and throughout the body, playing crucial roles in reward-motivated behavior, motor control, mood regulation among other functions. Overactivity of dopamine transmission is implicated in certain psychiatric disorders such as psychosis or schizophrenia. Therefore, by decreasing dopamine activity through receptor blockade, Compazine can limit excitatory effects on neuronal circuits thereby helping patients manage their condition and stabilize their mood.

Thorazine works similarly to Compazine but has been around longer and is considered one of the first-generation or typical antipsychotics with more side effect profile compared to second generation antipsychotics like Compazine due its broader action not only on dopamine receptors but also additional blockage of histamine H1 receptors causing sedation; muscarinic M1 receptors leading to dry mouth; α1-adrenergic receptors resulting hypotension; causing more incidence extrapyramidal side effects which include movement disorders like dystonia (continuous spasms), akathisia (restlessness) etc.

What is Thorazine?

Thorazine, which is a brand name for chlorpromazine, is a type of medication known as a typical antipsychotic. This means it works by blocking dopamine receptors in the brain, therefore reducing the activity of dopamine, a neurotransmitter that plays key roles in motivation and reward. Thorazine was first approved by the FDA back in 1953 and has been instrumental in treating psychiatric disorders such as schizophrenia and bipolar disorder. Unlike atypical antipsychotics like Compazine (prochlorperazine), Thorazine does not selectively target serotonin receptors over dopamine ones. As such, its side-effect profile differs from that of drugs like Compazine; specifically, it can cause extrapyramidal symptoms like muscle stiffness or tremors more frequently than newer antipsychotics. However, this effect on both serotonin and dopamine can be beneficial particularly for patients who do not respond well to “typical” atypical antipsychotic medications such as Compazine.

What conditions is Thorazine approved to treat?

Thorazine is a medication that has been approved by the FDA for the treatment of:

  • Schizophrenia, particularly for symptoms such as hallucinations, delusions, and hostility
  • Manic phase of manic-depressive disorder (bipolar disorder)
  • Severe behavioral problems in children aged 1 to 12 years old

How does Thorazine help with these illnesses?

Dopamine is a neurotransmitter that plays significant roles in the brain's reward system, motivation, and various other functions. Thorazine works by blocking dopamine receptors in the brain, which helps to manage symptoms of mental disorders such as schizophrenia or mania. Its action on other neurotransmitters may also contribute to its effectiveness as an antipsychotic medication. Because it significantly affects dopamine levels, Thorazine is often prescribed when a patient does not respond well to less potent antipsychotics like Compazine. It can also work effectively for nausea or vomiting situations where treatments with other drugs have failed.

How effective are both Compazine and Thorazine?

Both prochlorperazine (Compazine) and chlorpromazine (Thorazine) have established histories of use in treating severe nausea, vomiting, and psychotic disorders. These medications were approved by the FDA in the 1950s, marking the beginning of modern psychopharmacology. Since they act on different receptors and neurotransmitters, these two antipsychotic drugs may be prescribed under different circumstances.

The effectiveness of Compazine versus Thorazine has been evaluated in several clinical trials over time; one such trial conducted during the late 1970s compared their efficacy for controlling postoperative nausea and vomiting.[1] Both medications demonstrated similar effectiveness with an acceptable safety profile. However, patients receiving Compazine experienced somewhat fewer adverse effects related to sedation than those treated with Thorazine.

A review of multiple studies published through to 2016 indicates that prochlorperazine is a well-established treatment for nausea and vomiting associated with conditions such as migraines or chemotherapy-induced nausea.[2] This research also suggests that it is generally well-tolerated across various age groups including elderly populations. It has even found application beyond its initial uses as antiemetic therapy due to its unique pharmacological action.

Chlorpromazine continues to be regarded as an effective first-generation antipsychotic medication but tends to be used less frequently today due to potentially significant side effect profiles including constipation, dry mouth, weight gain and potential extrapyramidal symptoms or tardive dyskinesia[3]. Nonetheless, it may still play a role when other treatments have proven ineffective or intolerable for certain individuals suffering from schizophrenia or other psychiatric illnesses.

References: [1] https://pubmed.ncbi.nlm.nih.gov/27759/ [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5147394/ [3] https://www.drugs.com/sfx/chlorpromazine-side-effects.html

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At what dose is Compazine typically prescribed?

Oral dosages of Compazine range from 5–10 mg, taken 3-4 times per day for adults. However, studies have shown that a dosage of 5 mg three times daily is generally sufficient to control severe nausea and vomiting. For children aged between two and twelve years old, the recommended starting dose is 2.5 mg given twice or three times daily, which can be adjusted based on their weight and response to treatment. The maximum daily dosage should not exceed 40 mg in any case unless directed otherwise by a healthcare professional.

At what dose is Thorazine typically prescribed?

Thorazine treatment typically begins with a dosage of 25-50 mg, three to four times per day. The dose can then be increased to 400mg/day or more, divided into several doses throughout the day, based on individual response and tolerance. In some severe cases, the maximum dose may reach up to 2000 mg/day divided into multiple doses; however, this should only be considered under close medical supervision if there is no significant improvement at lower dosages after an appropriate period. It's important to note that Thorazine should always be taken as directed by your healthcare provider due its potential side effects and interactions.

What are the most common side effects for Compazine?

Common side effects of Compazine (prochlorperazine) may include:

  • Blurred vision, dry mouth
  • Stuffy nose
  • Constipation or mild diarrhea
  • Drowsiness, dizziness
  • Decreased sweating and increased sensitivity to sunlight
  • Menstrual irregularities for women
  • Swelling breasts in both men and women; missed menstrual periods.

Meanwhile, Thorazine (chlorpromazine) can have similar but more severe side effects such as:

  • Excessive salivation
  • Drowsiness, dizziness
  • Hypotension (low blood pressure)
  • Impotence or difficulty having an orgasm,
  • Constipation
  • Nasal congestion.

Both medications can also cause extrapyramidal symptoms which are movement disorders that can manifest as restlessness, tremors, and muscle stiffness. Always consult your doctor if you experience any of these side effects.

abstract image of a patient experiencing side effect

Are there any potential serious side effects for Compazine?

While both Compazine and Thorazine are antipsychotic medications, they each come with their own risks. Here's what you need to know about potential side effects from these drugs:

  • Extreme restlessness or anxiety
  • Signs of an allergic reaction such as hives; difficulty breathing; swelling in your face, lips, tongue, or throat.
  • Vision changes like blurred vision, tunnel vision, eye pain or seeing halos around lights
  • Unusual heartbeats: fast pounding heartbeats or fluttering in your chest leading to shortness of breath and a sudden feeling that you might pass out
  • Symptoms relating to low sodium levels - headache, confusion, slurred speech accompanied by severe weakness and vomiting along with loss of coordination resulting in a general unsteady feeling.
  • Severe reactions involving the nervous system – very stiff muscles (rigidity), high fever causing excessive sweating which leads to confusion followed by uneven heartbeats; tremors creating a sensation where one might feel like passing out
  • Any symptoms suggestive of serotonin syndrome including agitation onset hallucinations followed by fever sweating shivering rapid heartbeat muscle stiffness twitching loss of coordination nausea vomiting diarrhea.

If any of these symptoms occur while taking either Compazine or Thorazine immediately consult with your healthcare provider.

What are the most common side effects for Thorazine?

The medication Thorazine can cause various side effects including:

  • Dry mouth, nasal congestion
  • Blurred vision
  • Nausea or vomiting, constipation, loss of appetite
  • Difficulty sleeping (insomnia)
  • Shaking (tremors), perspiration, feeling anxious or agitated
  • An accelerated heart rate
  • Confusion and irritability
  • Skin rash or itching
  • Changes in weight
  • Increased frequency of urination
  • Headaches and dizziness
    -Muscle stiffness or spasm.

It's important to note that these are potential side effects and may not occur in every individual taking the drug. Always consult with a healthcare professional for personalized information regarding medications.

Are there any potential serious side effects for Thorazine?

While Thorazine is an effective medication for many, it does come with potential risks. These might include:

  • Allergic reactions such as hives, difficulty breathing or swallowing, and swelling of the face, lips, tongue or throat
  • Neuroleptic malignant syndrome which can cause high fever, stiff muscles, confusion and increased heartbeats
  • Tardive dyskinesia characterized by uncontrollable movements in your face (like chewing motions), tongue or other parts of your body
  • Unusual thoughts or behavior including hallucinations and seizures
  • Changes in vision like blurred sight or seeing halos around lights
  • Rapid heartbeat patterns that are irregular
  • Signs indicative to a shift towards mania: excessive happiness or irritability; racing thoughts; an increase in energy levels; reckless behavior; talking more than usual; sleep disturbances.

If any of these side effects are experienced while taking Thorazine, immediate medical attention should be sought.

Contraindications for Compazine and Thorazine?

Both Compazine and Thorazine, like other antipsychotic medications, may worsen symptoms of certain mental or mood disorders in some people. If you notice your condition worsening, or an increase in suicidal ideation, thoughts, or behavior while taking these medicines, please seek immediate medical attention.

Neither Compazine nor Thorazine should be taken if you are currently using large amounts of alcohol or substances with CNS depressant (central nervous system) properties such as sedatives. Always inform your physician about all the medications you are taking; substances with CNS depressant effects will require a suitable period to clear from your system to prevent dangerous interactions with both Compazine and Thorazine.

How much do Compazine and Thorazine cost?

For the brand name versions of these drugs:

  • The price for 60 tablets of Compazine (prochlorperazine) at a dose of 5 mg averages around $100, which works out to approximately $3.33/day.
  • The price for 30 tablets of Thorazine (chlorpromazine) at a dose of 50 mg is about $200, working out to roughly $6.67/day.

Thus, if you are in the higher dosage range for Compazine (i.e., up to 40 mg/day), then brand-name Thorazine may be less expensive on a per-day treatment basis depending on your specific dosage. Please note that cost should not be a primary consideration in determining which of these drugs is right for you.

For the generic versions chlorpromazine and prochlorperazine, costs are significantly lower:

  • Prochlorperazine is available in packs from as few as ten up to hundreds with approximate costs ranging from $0.15 to $1.00 per day based on dosages varying between 5mg/day and upwards.
  • Chlorpromazine can also be found in quantities similar to those mentioned above with cost starting from around $0.20/day going up to about $.90/day depending upon daily dosage requirements.

Remember that choosing medication should involve careful consultation with your healthcare provider regarding efficacy, side effects, interactions with other medications or medical conditions besides just considering the cost factor alone.

Popularity of Compazine and Thorazine

Prochlorperazine, in generic form as well as brand names such as Compazine, was estimated to have been prescribed to about 1.2 million people in the US in 2020. Prochlorperazine accounted for just over 15% of phenothiazine prescriptions in the US. It is a typical antipsychotic drug that also has antiemetic properties and is commonly used for nausea and vomiting associated with anesthesia, radiation therapy or chemotherapy.

Chlorpromazine, including brand versions such as Thorazine, was prescribed to approximately 600,000 people in the USA during the same year. In the US, chlorpromazine accounts for around 8% of phenothiazine prescriptions and it's often used off-label due to its calming effects on various types of psychosis not responding to other treatment attempts. The prevalence of chlorpromazine has been generally decreasing since it’s introduction back in late ‘50s due to emergence of newer generation antipsychotics which offer less side-effects.


Both Compazine (prochlorperazine) and Thorazine (chlorpromazine) have long-standing records of usage in patients with severe nausea, vomiting, and psychiatric disorders. These medications are backed by numerous clinical studies indicating that they are more effective than placebo treatments. Due to their different mechanisms of action, with Compazine acting primarily as a potent antiemetic and Thorazine used for broader indications like schizophrenia, they tend to be prescribed under different circumstances.

Compazine is often considered as a first-line treatment option for severe nausea and vomiting; whereas Thorazine can be utilized for various conditions including manic-depressive disorder and the manic phase of bipolar disorder. Both drugs may require an adjustment period due to potential side effects which vary between individuals but usually resolve over time.

While both medications are available in generic form representing significant cost savings especially for patients who must pay out-of-pocket, it's important to note that these drugs should not be used without careful consideration by a healthcare provider due to their powerful nature.

The side-effect profile is similar between the two drugs although Compazine has less sedative effect compared to Thorazine. For both drugs, it is advisable for patients or caregivers to closely monitor response while on this medication particularly when starting treatment or adjusting doses. Any changes in behavior or worsening symptoms should prompt immediate medical attention.