Cinnarizine for PONV: When It Helps After Surgery, Evidence and Safety (2025)

Post-op nausea and vomiting can ruin an otherwise smooth recovery. If you’re scanning for options beyond the usual ondansetron and dexamethasone, you might be wondering where cinnarizine fits. Short answer: it’s not first-line for PONV, but there are narrow, practical situations where it can help-mainly as an oral add-on once the patient can swallow and standard agents are in place.

• PONV still affects about 30% of adults after general anaesthesia and up to 80% if you’re high risk (Apfel score 3-4).
• Cinnarizine is an H1 antihistamine/calcium-channel blocker used for motion sickness; for PONV its evidence is limited and it’s off-label.
• In 2025 UK practice, standard PONV prophylaxis is ondansetron, dexamethasone, droperidol/haloperidol, and cyclizine-not cinnarizine.
• Consider cinnarizine only when oral meds are tolerated, IV options are used/contraindicated, and sedation risk is low.
• Safety watch-outs: drowsiness, anticholinergic effects, interactions with CNS depressants, and extrapyramidal risk with prolonged use.

What is cinnarizine and does it help with PONV?

Cinnarizine has been around since the 1950s. In the UK, you’ll recognise it from travel-sickness shelves (often 15 mg tablets). Mechanism-wise, it blocks H1 histamine receptors and mildly blocks calcium channels in the vestibular system. That combo calms inner-ear overstimulation, which is why it helps motion sickness and vertigo.

Postoperative nausea and vomiting (PONV), though, is a different beast. It’s a mix of anaesthetic effects, surgical factors, opioids, and patient risk. Modern PONV management is built on good risk stratification (Apfel score), minimising emetogenic triggers, and giving evidence-backed antiemetics with different mechanisms. UK and international guidelines (NICE Medicines Evidence commentary, Royal College of Anaesthetists, and SAMBA/ASA-ERAS consensus) consistently centre on 5-HT3 antagonists (ondansetron), dexamethasone, dopamine antagonists (droperidol/haloperidol), and antihistamines-specifically cyclizine-not cinnarizine.

So, does cinnarizine work? There are small, older trials-mainly ENT and minor surgery settings-suggesting it can reduce nausea scores versus placebo and may delay vomiting onset. But the evidence is thin, heterogenous, and not robust enough to land in guidelines. You won’t find modern, high-powered RCTs comparing it head-to-head with ondansetron or dexamethasone for PONV. Because of that, its role is secondary, off-label, and opportunistic.

One more pitfall to clear up: cinnarizine and cyclizine are not the same drug. Cyclizine is widely used perioperatively in the UK (including IV), has better PONV data than cinnarizine, and appears in hospital PONV protocols. Cinnarizine is oral-only, more sedating for many people, and stays outside mainstream PONV pathways.

Evidence and how it compares to standard antiemetics in 2025

Let’s put it in context. Here’s how the usual suspects fare for PONV prevention and treatment, summarised from guideline statements (Royal College of Anaesthetists 2020 update, SAMBA 2020 consensus), Cochrane reviews, and the BNF. Figures are rounded heuristics to help decisions, not exact meta-analytic outputs for every surgery type.

Where does that leave cinnarizine? A reasonable summary for 2025 UK practice:

• Not recommended for routine PONV prophylaxis.
• Considered only as an oral rescue or add-on when standard therapy is used or unsuitable and the patient can safely swallow.
• Might be appealing in late PONV (after discharge) when access to IV meds is gone and vestibular-type nausea dominates (spinning, motion-triggered symptoms).

What about day-case surgery? Many patients go home within hours. If PONV flares later that evening, a clinician might suggest a short course of oral antiemetics. Here, in specific cases, a prescriber could choose cinnarizine if standard oral agents aren’t available or tolerated. Reminder: for PONV this is off-label; it should be clinician-directed, not self-medication.

Practical use: who might get it, dosing, timing, and combinations

First, a quick rule of thumb: if the patient can’t tolerate oral fluids or is at risk of aspiration, cinnarizine is a non-starter. You need IV options. If they can sip and keep fluids down, and you’ve already used (or can’t use) the usual antiemetics, cinnarizine can be considered as a short-term adjunct.

Typical regimens used in practice (guided by BNF dosing for motion sickness/vestibular disorders and adapted cautiously for postoperative settings):

• Adults: 15-30 mg orally up to three times daily, short-term. Many clinicians cap at 2-3 days post-op. Start low if elderly or sensitive to sedation.
• Timing: Give when oral intake is possible. If used for late PONV at home, a prescriber might advise an evening dose when drowsiness is less disruptive.
• Do not stack with other sedating antihistamines or strong CNS depressants right away. Space doses and review the drug chart.

Combination logic (keep mechanisms different to get additive benefit):

• Already had dexamethasone in theatre? Good. Add a 5-HT3 (ondansetron) or a dopamine antagonist for rescue before thinking about antihistamines.
• If cyclizine helped in recovery but nausea returned later at home and the patient is very drowsy with it, a prescriber might switch strategy. Cinnarizine may still cause drowsiness, but some patients report it as more tolerable at lower doses taken at night.
• Avoid doubling up antihistamines without a specific reason; choose one.

Who might be a sensible candidate?

• Low-moderate risk patient with late-onset PONV, can swallow, and had side effects on other rescue options.
• Vestibular-dominant symptoms: movement triggers waves of nausea, spinning, eye-movement sensitivity.
• Settings with limited access to standard agents post-discharge, provided a clinician reviews the case.

Who is not a good candidate?

• High-risk PONV patient in the first hours post-op needing rapid IV rescue.
• People who must avoid sedation: airway risk, untreated sleep apnoea, post-neurosurgery where neuro exams matter, anyone who must mobilise safely without falls.
• Patients on multiple anticholinergics or strong CNS depressants (e.g., benzodiazepines, opioids at higher doses) without close review.

Simple decision tree you can borrow:

1. Can the patient swallow and keep fluids down? If no, don’t use oral antihistamines; use IV rescue.
2. Have you already used two classes (e.g., dexamethasone + ondansetron)? If no, add a different class first.
3. Any red flags for sedation or anticholinergic burden (confusion, urinary retention, glaucoma)? If yes, avoid.
4. Vestibular features prominent and late PONV at home? Consider a short course if a prescriber agrees and counsels the patient.

Practical tip from the ward: write clear discharge advice. Many patients panic when nausea returns at midnight. A simple plan-fluids first, small sips, a prescribed rescue tablet if needed, when to call-keeps people safe and out of A&E.

Safety, pitfalls, checklists, and FAQ

Safety profile in a nutshell:

• Common: drowsiness, dry mouth, mild blurred vision, constipation.
• Less common but important: confusion or agitation in older adults, urinary retention (especially in men with prostate issues), hypotension, photosensitivity.
• Rare: extrapyramidal symptoms with longer courses (days to weeks), especially in older adults or those with Parkinson’s disease-hence the push to keep post-op use very short.

Drug interactions and cautions:

• CNS depressants (opioids, benzodiazepines, gabapentinoids, alcohol): additive sedation. Space doses, lower totals, or choose a non-sedating class instead.
• Anticholinergics (e.g., oxybutynin, amitriptyline): higher risk of confusion, dry mouth, urinary retention, constipation.
• Parkinson’s disease: antihistamines with anticholinergic properties can worsen symptoms; discuss alternatives.
• QT issues: cinnarizine isn’t the biggest QT offender, but stacking multiple QT-prolonging drugs post-op (ondansetron, droperidol) warrants caution and clinical judgment.
• Pregnancy/breastfeeding: PONV management differs; use guideline-backed agents. Don’t add off-label antihistamines without obstetric input.

Regulatory and guideline context (UK, 2025):

• BNF lists cinnarizine for motion sickness/vestibular disorders; PONV use is off-label and clinician-led.
• NICE, Royal College of Anaesthetists, and ERAS/SAMBA guidance for PONV do not include cinnarizine as a standard option.
• Hospitals typically stock cyclizine, not cinnarizine, for perioperative antihistamine use; cyclizine is available IV/IM and orally.

Checklist: deciding on cinnarizine for late PONV

• Oral intake possible (no persistent vomiting, no aspiration risk).
• Two different standard classes attempted or contraindicated.
• Low falls/sedation risk; supervision available at home if drowsy.
• No major anticholinergic burden; bowels and bladder okay.
• Clear stop date (usually 48-72 hours max) and review plan.

Common pitfalls to avoid:

• Confusing cinnarizine with cyclizine on the drug chart. Double-check the name, dose, and route.
• Starting it too early post-op when the patient still needs IV rescue.
• Layering multiple sedating meds without warning the patient about drowsiness and falls risk.
• Letting it run on for weeks. Keep it short and purpose-built.

Mini-FAQ

Is cinnarizine good for everyone with PONV?

No. It’s not standard and not for early, severe PONV. It’s a niche, oral add-on when other routes or classes aren’t working or available.

Is it safe right after general anaesthesia?

If the airway is secure and the patient can swallow, it can be considered. But in the first hours, IV agents with stronger evidence are a better bet.

Can patients self-medicate with over-the-counter cinnarizine for PONV at home?

They shouldn’t. PONV is not the same as travel sickness. Off-label use needs a prescriber’s advice because of sedation, interactions, and the need to rule out surgical complications.

What’s the usual dose?

For motion sickness, BNF adult dosing is typically 15-30 mg up to three times a day. In PONV, prescribers usually start low and limit to a short course, tailored to the individual.

Does it help if ondansetron has failed?

Maybe, but not reliably. Better to use a different class with stronger evidence first (e.g., droperidol/haloperidol or cyclizine). Cinnarizine might be tried later if oral and appropriate.

Is cyclizine better than cinnarizine?

For perioperative use, yes. Cyclizine has more PONV data, is available IV, and appears in hospital protocols. Cinnarizine is mostly for motion sickness and is oral-only.

What about kids?

Paediatric PONV protocols are specific. Don’t improvise with off-label antihistamines; stick to paediatric guidelines and specialist advice.

When should someone seek help?

If vomiting persists beyond 24 hours, there’s severe abdominal pain, fever, or signs of dehydration, they should contact their surgical team or NHS 111. Sudden worsening can signal a surgical issue, not just PONV.

Next steps and troubleshooting for different scenarios

• Day-case laparoscopy, high PONV risk (Apfel 3-4): Build prophylaxis with dexamethasone + ondansetron; consider droperidol. Discharge with a plan for oral rescue (often ondansetron or prochlorperazine). Only consider cinnarizine if standard oral rescue fails and a prescriber agrees.
• ENT surgery with vestibular symptoms post-op: If IV rescue works in recovery but nausea returns at home and is movement-triggered, a clinician might trial short-course oral vestibular agents. Cinnarizine can be one option, with strict cautions on sedation and short duration.
• Elderly patient on opioids: Prioritise non-sedating agents first. If any antihistamine is used, go low and slow, review daily, and watch for confusion or urinary retention.
• Breastfeeding parent: Use guideline-backed antiemetics with established lactation safety data. Avoid off-label cinnarizine unless a specialist endorses it.

Pro tips

• Think in classes. If a 5-HT3 fails, try a different mechanism before stacking similar effects.
• Document the stop date when prescribing sedating antihistamines post-op.
• Educate: Sips of fluid, bland snacks, slow position changes, and pain control can prevent a spiral of nausea.

Final word: PONV is common and fixable with the right mix of prevention and rescue. Cinnarizine isn’t a star player here, but in the right hands and the right moment-usually late, oral, short-term-it can still move the needle for a few patients. As someone who’s juggled kids’ tea, school runs in Bristol, and post-op recovery in the same week, I’ll take any safe, sensible edge we can get-provided it’s guided by solid clinical judgment.