Part of the Access Doctor nausea & vomiting guide.
Prochlorperazine (Stemetil) for Nausea & Vertigo: UK Prescription Guide
A clinically reviewed UK guide to prochlorperazine — how it works, Stemetil vs Buccastem, dosing, side effects, who cannot take it, and how to get it without a GP appointment.
5–10mg
Standard oral/buccal dose for nausea and vertigo
Rx only
Prescription-only in the UK
D2 blocker
Dopamine antagonist — acts on the chemoreceptor trigger zone
Buccal
Dissolves between gum and cheek — useful when vomiting prevents swallowing
▶ Quick summary
Prochlorperazine is a prescription dopamine antagonist used to treat nausea, vomiting, and vertigo in the UK. It acts on the chemoreceptor trigger zone (CTZ) and is available as tablets, buccal tablets (Buccastem), and injection. It is particularly useful for vertigo-related nausea and acute vomiting where swallowing is difficult.
How Prochlorperazine Works
Prochlorperazine belongs to the phenothiazine class and works primarily by blocking dopamine D2 receptors in the chemoreceptor trigger zone (CTZ) — the brain structure that samples the bloodstream for nausea-triggering signals and relays them to the vomiting centre. Blocking D2 receptors at the CTZ interrupts this relay and reduces the urge to vomit.
It also has antihistamine and anticholinergic properties, which contribute to its effectiveness for vertigo-related nausea by dampening signals from the vestibular system. This dual action — CTZ blockade plus vestibular dampening — makes it effective across a broader range of nausea types than either mechanism alone would provide.
Unlike domperidone, prochlorperazine does cross the blood–brain barrier. This gives it access to central dopamine receptors and explains its effectiveness for vertigo — but it also means it can cause central side effects (drowsiness, extrapyramidal reactions) that domperidone does not.
Tablets, Buccal Tablets, and Injection
| Form | Brand | Notes |
|---|---|---|
| Oral tablets | Stemetil 5mg | Most common form. Taken by mouth with water. Standard first choice for outpatient use. |
| Buccal tablets | Buccastem M 3mg | Placed between the upper gum and cheek, where they dissolve slowly. Useful when nausea makes swallowing difficult or when vomiting is persistent. Available without prescription. |
| Injection (IM) | Stemetil | Hospital/clinic use only for acute severe vomiting. Not for self-administration. |
Buccastem M buccal tablets (3mg) are available at UK pharmacies without a prescription specifically for the treatment of nausea associated with previously diagnosed migraine. For other indications, prescription prochlorperazine is required.
What Is Prochlorperazine Used For?
- Vertigo-related nausea — including labyrinthitis, vestibular neuritis, BPPV (when the nausea component is dominant), and Menière’s disease. NICE CKS lists prochlorperazine as first-line or second-line for acute vestibular nausea alongside cyclizine.
- Migraine-associated nausea and vomiting — Buccastem is specifically licensed for this; its buccal route avoids the absorption problems caused by migraine-induced gastric stasis.
- Nausea and vomiting of central or metabolic origin — effective when the CTZ is the dominant pathway (e.g. uraemia, drug-induced nausea).
- Post-operative nausea and vomiting (PONV) — used in hospital settings.
Not recommended for: gastroenteritis or food poisoning (domperidone or metoclopramide better suit gastric-pathway nausea) · nausea in pregnancy (avoid phenothiazines unless specialist advice; cyclizine is first-line for NVP) · motion sickness (cyclizine or hyoscine are preferred).
Dosing Guidance
| Form | Dose | Frequency | Notes |
|---|---|---|---|
| Stemetil tablets | 5mg | Up to three times daily | Take with or after food. Maximum 30mg in 24 hours. |
| Buccastem M buccal | 3mg (one tablet) | 1–2 times daily | Place between upper gum and cheek. Do not chew, suck or swallow. Dissolves over 1–2 hours. |
Elderly patients: use the lowest effective dose and monitor closely. Prochlorperazine is associated with an increased risk of falls, sedation, and extrapyramidal effects in older adults. MHRA advises caution.
Side Effects
Most people tolerate prochlorperazine well at standard doses for short courses. Common side effects include drowsiness and mild dizziness. The more clinically important ones are:
- Extrapyramidal reactions — muscle stiffness, restlessness, tremor, involuntary movements. More common with higher doses or prolonged use. If these occur, stop the medicine and seek medical advice.
- Drowsiness — avoid driving or operating machinery until you know how it affects you.
- Postural hypotension — dizziness on standing, particularly in elderly patients.
- Raised prolactin — relevant with long-term use; not a concern for short courses.
Seek urgent help if you develop: severe muscle rigidity, high fever, rapid heart rate, and altered consciousness — these may indicate neuroleptic malignant syndrome, a rare but serious reaction requiring emergency care.
Who Should Not Take Prochlorperazine
- Children under 10 years (unless under specialist supervision)
- Pregnancy — especially first trimester; use only if other options have failed and under clinical guidance
- Parkinson’s disease — dopamine antagonists worsen motor symptoms
- History of bone marrow depression or blood dyscrasias
- Severe cardiovascular disease
- QT-prolonging medicines — combination increases cardiac arrhythmia risk
Prochlorperazine vs Cyclizine for Vertigo Nausea
| Prochlorperazine | Cyclizine | |
|---|---|---|
| Mechanism | D2 antagonist + anticholinergic | H1 antihistamine + anticholinergic |
| Best for vertigo nausea | Yes — strong CTZ + vestibular action | Yes — vestibular dampening |
| Also treats migraine nausea | Yes (Buccastem licensed) | Yes |
| Drowsiness | Moderate | Moderate |
| Safe in pregnancy | Avoid if possible | First-line (RCOG) |
| OTC available | Buccastem 3mg for migraine only | Yes (50mg) |
| Extrapyramidal risk | Yes (especially high dose/elderly) | No |
For a full guide to cyclizine including vertigo, motion sickness, and pregnancy use: Cyclizine: complete UK guide →
Getting Prochlorperazine in the UK
Stemetil 5mg tablets require a prescription. Buccastem M 3mg buccal tablets are available over the counter at UK pharmacies for migraine-associated nausea in adults who have a confirmed diagnosis of migraine. For other indications, or if you need the tablet form, a prescription is required.
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View Nausea Treatments →Frequently Asked Questions
What is prochlorperazine used for in the UK?
Prochlorperazine is used to treat nausea and vomiting caused by vertigo, migraine, post-operative sickness, and nausea of central or metabolic origin. Buccastem M buccal tablets are specifically licensed for migraine-associated nausea and are available over the counter. Stemetil tablets require a prescription.
What is the difference between Stemetil and Buccastem?
Both contain prochlorperazine but differ in dose and route. Stemetil 5mg is an oral tablet taken with water, used across a range of nausea indications, and requires a prescription. Buccastem M 3mg is a buccal tablet that dissolves between the gum and cheek — useful when vomiting makes swallowing difficult — and is available OTC specifically for migraine nausea.
Can I take prochlorperazine every day?
Short courses are appropriate for acute nausea. Prolonged daily use increases the risk of extrapyramidal side effects, raised prolactin, and dependence on antiemetics. If you find yourself needing an antiemetic every day, speak to a GP about the underlying cause.
Is prochlorperazine safe in pregnancy?
Prochlorperazine should generally be avoided in pregnancy, particularly the first trimester. Cyclizine is the preferred first-line antiemetic for nausea and vomiting of pregnancy per RCOG guidance. If symptoms are severe and other options have failed, use under clinical supervision only.
Can I drive after taking prochlorperazine?
Prochlorperazine causes drowsiness in some people. You should not drive or operate machinery until you know how it affects you. This is particularly important with the first dose.
References
- NICE CKS. Vertigo. Updated 2023. cks.nice.org.uk
- BNF. Prochlorperazine. bnf.nice.org.uk
- NHS. Prochlorperazine. nhs.uk/medicines/prochlorperazine
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any treatment. In a medical emergency, call 999.