What is prochlorperazine, and how does it work (mechanism of action)?
Prochlorperazine is an antiemetic (to
control nausea and vomiting) and first generation antipsychotic agent.
Prochlorperazine is one of the older first-generation piperazine phenothiazine
antipsychotic medications. Examples of other phenothiazines include:
- fluphenazine (Permitil,
- chlorpromazine (Promapar, Thorazine)
- fluphenazine (Permitil,
- perphenazine, trifluoperazine (Stelazine)
Although, the exact mechanism of phenothiazine antipsychotics is unknown,
scientists believe that they may work by blocking the action of dopamine in the
brain. Dopamine is a neurotransmitter (chemical) that nerves use to communicate
with one another. Phenothiazine antipsychotics are used when patients do not
respond to other antipsychotics.
The antiemetic benefits of prochlorperazine are due to dopamine blockade in
the chemoreceptor trigger zone of the brain. Additionally, prochlorperazine has
moderate effects on other neurotransmitters and receptors. Blockade of certain
receptors called alpha-adrenergic receptors causes drowsiness, muscle
relaxation, and adverse cardiovascular effects such as low blood pressure,
reflex tachycardia, and changes in heart rhythm.
Prochlorperazine was approved by the US Food and Drug Administration (FDA) in
What brand names are available for prochlorperazine?
Is prochlorperazine available as a generic drug?
Do I need a prescription for prochlorperazine?
What are the side effects of prochlorperazine?
Side effects associated with prochlorperazine treatment include:
- Skin reactions
- Low blood pressure
The following also have been reported are movement disorders (extrapyramidal
Additionally, cardiac (heart) and liver
abnormalities have occurred in some patients.
Children are prone to develop extrapyramidal reactions more than adults.
What causes tooth decay?
Which drugs or supplements interact with prochlorperazine?
- Acetylcholinesterase inhibitors may decrease the effectives of
prochlorperazine. Centrally acting acetylcholinesterase inhibitors may increase
the neurotoxic effects of antipsychotic agents.
- Combining prochlorperazine with alcohol,
kava kava, CNS depressants, and
cannabis may increase the risk of CNS depressant side effects.
- Antacids may decrease the absorption of prochlorperazine.
- Prochlorperazine may cause anticholinergic side effects such as
dry eyes, decreased urinary output, and mental
Combining agents with similar anticholinergic effects increases the risk of
experiencing such adverse events.
- Prochlorperazine may increase the blood levels of dofetilide (Tikosyn).
Use of both drugs is not recommended.
- Deferoxamine (Desferal) may increase the risk of experiencing side effects of
prochlorperazine treatment. Combination use has resulted in the prolonged loss
Metoclopramide (Reglan) may increase the side effects of antipsychotic
agents. Combination use is not recommended.
- Prochlorperazine may increase the CNS depressant effects of orphenadrine (Norflex)
or paraldehyde (Paral). Combination use is not recommended.
- Combining prochlorperazine and
potassium chloride may result in an increase
in the ulcerogenic effect of potassium chloride (Klor-Con). Combination use is
generally not recommended.
- Combining prochlorperazine with
(Thalomid) may increase the risk of
experiencing CNS depressant side effects. This combination is generally not
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Is prochlorperazine safe to take if I’m pregnant or breastfeeding?
Prochlorperazine has not been adequately evaluated in pregnant women. Due to the lack of conclusive safety data, prochlorperazine should be
avoided in pregnancy except in cases of severe nausea and vomiting that requires
treatment and potential benefit justifies the potential risk to the fetus.
It is not known if prochlorperazine is excreted into human
milk. Other phenothiazines are excreted into breast milk. If clearly needed, prochlorperazine
should be used cautiously in females who are nursing.
What else should I know about prochlorperazine?
What preparations of prochlorperazine- are available?
- Prochlorperazine Edisylate solution for injection: 5 mg/ml
- Prochlorperazine Maleate oral tablet: 5 mg, 10 mg
- Prochlorperazine rectal suppository: 2.5, 5, 25 mg
How should I keep prochlorperazine stored?
Prochlorperazine injection solution is recommended to be stored
below 30 C (86 F). All other dosage forms may be stored between 15 C to 30 C (59
F to 86 F).
Treatment of severe nausea and vomiting
- The dosage must be adjusted
based on individual patient response.
- Patients are generally started on the
lowest recommended dosage.
- Oral tablets: The usual recommended dose is one 5 mg or 10 mg tablet orally
3-4 times daily.
- Rectal suppository: 25 mg twice daily.
- Intramuscular injection: The usual starting dose is 5 to 10 mg injected
deeply into the upper outer quadrant of the buttock. Additional doses may be given
every 3 or 4 hours as necessary. Total daily dose should not exceed 40 mg per
day except in resistant patients.
- Intravenous (IV) dosage: The usual recommended dose is 2.5 to10 mg by slow IV
injection or infusion at a rate not to exceed 5 mg per minute. A single dose should not exceed 10 mg.
The total daily dose should not exceed 40 mg
Adult surgery patients with severe nausea or vomiting
- The total daily dose
should not exceed 40 mg per day.
- Intramuscular injection: The usual recommended dose is 5 to 10 mg, 1 to 2
hours before the administration of anesthesia. A second dose may be given in 30
minutes if necessary. Repeat doses may also be given to control acute symptoms
during and after surgery as needed.
- IV dosage: The usual recommended dose is 5 to 10 mg as a slow IV injection or
infusion 15 to 30 minutes before the administration of anesthesia, or to control
acute symptoms during or after surgery.
Adult psychiatric disorders
- Individual patient dosage is adjusted based on
response and severity of the condition. Treatment is started with the lowest
- Oral dosage: non-psychotic anxiety: The usual recommended dose is 5 mg 3-4
- Psychotic disorders including schizophrenia (mild): The usual recommended
dose is 5 to 10 mg 3-4 times daily.
- Psychotic disorders including schizophrenia (moderate to severe conditions):
The recommended usual starting dose in hospitalized or adequately supervised
patients is 10 mg 3-4 times daily. Dosage should be increased in small
increments every 2-3 days to minimize the occurrence of side effects. Some
patients may have a satisfactory response to 50 to 75 mg per day. Patient with
severe symptoms may require 100 to 150 mg per day.
- Intramuscular dosage: For the immediate control of severe schizophrenia
symptoms in adult patients, patients may be started with an initial dose of 10
to 20 mg administered deeply into the upper outer quadrant of the buttock.
Repeat injections may be given every 2 to 4 hours if necessary.
Pediatric use (dose calculation) is weight-based and the drug should not be
used in children < 2 years old.