• Prochlorperazine may be used to treat severe nausea and vomiting and some mental health conditions such as schizophrenia.
• Experts aren't sure exactly how prochlorperazine works in the treatment of psychosis and anxiety but believe it is due to its inhibition of dopamine, muscarinic, and histamine receptors.
• When used in the treatment of severe nausea and vomiting, prochlorperazine is thought to have a direct effect on the vomiting center and chemoreceptor trigger zone, both located in the medulla oblongata of the brain.
• Prochlorperazine belongs to the group of medicines known as phenothiazines.

• May be used in the treatment of anxiety and schizophrenia.
• Also used to treat severe nausea and vomiting.
• Prochlorperazine suppositories may be preferred over oral tablets for severe nausea and vomiting.
• Some forms of prochlorperazine (for example, the buccal tablet [which dissolves in the mouth under the top lip]) can be purchased over the counter.
• Generic prochlorperazine is available.

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

• Drowsiness, abnormal movements, restlessness, tremor, blurred vision, skin reactions, and low blood pressure are the most commonly reported side effects. Constipation, dry mouth, and leukopenia (low white blood cell count) are also common.
• Acute dystonic reactions (sustained muscle contractions that are frequently associated with twisting, abnormal postures, or repetitive movements) have occurred with prochlorperazine, more often in children and young adults.
• Potentially irreversible tardive dyskinesia (involuntary movements of the tongue, lips, and face) has also been reported in association with prochlorperazine use. Incidence is highest among elderly women.
• Associated with an increased risk of death in elderly patients with dementia-related psychosis. Do not use prochlorperazine in people with dementia.
• Not shown to be effective at managing behavioral complications in people with mental retardation.
• Should not be given to comatose patients or taken by people who have consumed large amounts of central nervous system depressants (such as alcohol, narcotics, barbiturates).
• May cause changes in electrocardiograms, such as nonspecific, usually reversible Q- and T-wave distortions.
• May not be suitable for people with a history of heart disease, respiratory disease, Parkinson's disease, elevated prolactin levels, with a history of alcohol use or exposure to organophosphate insecticides.
• Do not use in children under the age of 2 or in children under 20 pounds (9 kg) in weight. Seek medical advice before using prochlorperazine in any child.
• May mask the signs and symptoms of overdosage or obscure the diagnosis of certain conditions such as Reye's syndrome, intestinal obstruction, or a brain tumor.
• Has also been associated with Neuroleptic Malignant Syndrome (a potentially fatal condition associated with fever, rigidity, altered mental status, blood pressure, and heart rate changes).
• May interact with some other drugs including oral anticoagulants, anticonvulsants, thiazide diuretics, and propranolol.
• Not recommended during pregnancy except in cases of severe nausea and vomiting where the benefits outweigh the risks. Safety in pregnancy has not been established. Reports of prolonged jaundice, extrapyramidal signs, and hyper or hyporeflexia have been reported in newborn infants whose mothers received phenothiazines. Caution when administering during breastfeeding because it is likely prochlorperazine is secreted into breast milk.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

• May cause drowsiness and affect your ability to drive or operate machinery. Avoid alcohol while you are taking prochlorperazine.
• Hot weather may exacerbate the side effects of prochlorperazine, such as dizziness. When going from lying down to a standing position, do so slowly. Drink plenty of fluids throughout the day to maintain good hydration.
• If you experience any muscle-type effects (such as tremors or abnormal facial movements), unexplained fever, confusion, or a fast or irregular heartbeat, contact your doctor immediately.
• Only take prochlorperazine as recommended by your doctor. Some people may require a lower dosage - talk with your doctor if you are experiencing a lot of initial side effects.
• If using prochlorperazine suppositories, remove the suppository from the plastic packet. Lie down with one knee drawn into the chest, then insert the suppository as high as possible into the rectum.
• Prochlorperazine may make your skin more sensitive to sunburn. Always wear sunscreen and protective clothing when you are outside.
• Prochlorperazine can increase prolactin levels which may result in enlarged breasts, missed menstrual periods, or nipple discharge. Contact your doctor if any of these happen.
• Talk to your doctor or pharmacist before taking any other medications with prochlorperazine, including those bought over-the-counter, because some of these may not be compatible with prochlorperazine.
• Tell your doctor or other health professionals that you take prochlorperazine before any procedures are done.
• Not recommended during pregnancy or breastfeeding unless on a doctor's advice and the benefits outweigh the risks.

• The onset of the effect of prochlorperazine is within 30 to 40 minutes after oral administration, 10 to 20 minutes following intramuscular injection, and within 60 minutes of rectal administration.
• The intramuscular injection of prochlorperazine has a duration of action of three to four hours.

Medicines that interact with prochlorperazine may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with prochlorperazine. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with prochlorperazine include:

• amiodarone
• anticoagulants, such as warfarin
• antidepressants, such as escitalopram, and monoamine oxidase inhibitors, such as isocarboxazid, selegiline, or tranylcypromine
• antiepileptics, such as carbamazepine and phenytoin
• beta-blockers, such as sotalol
• benzodiazepines, such as diazepam, oxazepam, and temazepam
• buprenorphine
• bupropion
• clozapine
• metoclopramide
• opioids, such as methadone, oxycodone, morphine, or codeine
• potassium chloride
• sedatives, or any medication that causes sedation, such as sleeping pills or muscle relaxants
• thiazide diuretics, such as hydrochlorothiazide
• tramadol
• other medications used to treat allergies.

Alcohol may enhance the sedative effects of prochlorperazine.

Note that this list is not all-inclusive and includes only common medications that may interact with prochlorperazine. You should refer to the prescribing information for prochlorperazine for a complete list of interactions.