InfoSynergy
Magnesium Glycinate
Low magnesium increases vulnerability to torsades when QT-prolonging drugs are used.
Recommendation: Correct documented hypomagnesemia medically, especially with vomiting, diarrhea, diuretics, or cardiac disease.
Prochlorperazine
Prescription ·Strong evidence ·Reviewed May 2026
Prochlorperazine is a phenothiazine dopamine antagonist used for severe nausea, vomiting, and short-term treatment of nonpsychotic anxiety in some formulations. It can cause extrapyramidal symptoms, sedation, orthostatic hypotension, anticholinergic effects, QT prolongation, and neuroleptic malignant syndrome, and it carries the antipsychotic class boxed warning for increased mortality in elderly patients with dementia-related psychosis.
What it's good for
The bottom line
Evidence rating strong. Most-documented uses: control of severe nausea and vomiting, short-term treatment of nonpsychotic anxiety when other options are unsuitable, management of vestibular nausea or vertigo-related vomiting in selected patients. 3 sources indexed (1989–2026), with 4 interaction records on file.
The science
How it works, mechanistically.
Core mechanism
Prochlorperazine blocks dopamine D2 receptors in the chemoreceptor trigger zone and central nervous system, reducing nausea and vomiting and producing antipsychotic effects at higher exposures. Phenothiazine activity at alpha-adrenergic, histamine, muscarinic, and cardiac ion channels contributes to hypotension, sedation, dry mouth, urinary retention, extrapyramidal reactions, hyperprolactinemia, and QT-related arrhythmia risk.1,2
Class
Phenothiazine antiemetic and antipsychotic
Dosing
Dosing & protocol.
Common range
Adults: oral 5 to 10 mg three or four times daily for nausea or vomiting; rectal 25 mg twice daily may be used for severe symptoms. Use the lowest effective dose for the shortest duration.
Recommended form
Oral tablet, rectal suppository, or supervised injectable formulation depending on severity and ability to take oral medication
Oral doses may be taken with food if gastrointestinal upset occurs. Avoid alcohol and use caution with other sedating or QT-prolonging agents.
Safety
Full safety detail.
Side effects
- Drowsiness
- Dizziness
- Akathisia
- Dystonia
- Parkinsonism
- Tardive dyskinesia
- Orthostatic hypotension
- Dry mouth
- Constipation
- Urinary retention
- Photosensitivity
- QT prolongation
- Neuroleptic malignant syndrome
- Lowered seizure threshold
Contraindications
- Comatose states or severe central nervous system depression3
- Known hypersensitivity to phenothiazines2
- Pediatric use in children younger than 2 years or under 20 pounds3
- Avoid pediatric use for conditions where dosage has not been established3
- Use caution in Parkinson disease, seizure disorders, glaucoma, urinary retention, severe cardiovascular disease, or high QT risk
Interactions
Interaction records.
InfoSynergy
Potassium
Hypokalemia can increase QT-related arrhythmia risk during prochlorperazine therapy.
Recommendation: Correct low potassium under clinician guidance; avoid unsupervised potassium in kidney disease or with potassium-retaining drugs.
ModerateCaution
Melatonin
Melatonin can add to prochlorperazine-related sedation, dizziness, and psychomotor impairment.
Recommendation: Avoid combining before driving; use extra caution in older adults or fall-prone patients.
ModerateCaution
Ginkgo Biloba
Ginkgo has seizure case reports, and phenothiazines may lower seizure threshold in susceptible patients.
Recommendation: Avoid or use cautiously in seizure disorders or with other seizure-threshold-lowering exposures.
Sources
Sources, by evidence tier.
Numbered references. Citations throughout the page link here.
Reviews & position papers
2- 1Management of nausea and vomiting in adultsNeeds reviewNo linkFlake ZA et al. · American Family Physician · 2015
Clinical review describes antiemetic selection and adverse-effect tradeoffs for dopamine antagonists.
- 2Drug-induced movement disordersNeeds reviewNo linkMiller LG · Clinical Pharmacy · 1989
Review describes dopamine antagonist movement disorder risks and clinical recognition.
Reference material
1- 3Prochlorperazine Maleate Tablets US Prescribing InformationNeeds reviewURLU.S. National Library of Medicine · DailyMed · 2026
Labeling describes antiemetic use, dosing, boxed warning, pediatric restrictions, CNS depression, and extrapyramidal risks.
Keep exploring
Deep dives & adjacent profiles.
This page is educational. Do not start, stop, or change a supplement or medication based on it without checking with a qualified healthcare professional.
Use this with your stack
Prochlorperazine in NutriStack.
Add it to your stack, see how it interacts with everything else you take, and get a Stack Score that updates the moment it does.