Promethazine is used in the UK to prevent and treat motion sickness. It is generally more useful when taken before travel rather than waiting until you are already feeling sick. That is why the timing of your dose matters.
Phenergan is not a general treatment for every type of nausea. It can also be used for vomiting caused by vertigo, but the right treatment depends on what is causing your symptoms. Nausea from a stomach bug, migraine, pregnancy or a medicine side effect may need a different approach. This guide explains how promethazine works, when to take it, how it compares with other travel sickness medicines, and when you should speak to a pharmacist or doctor.
Key things to know
- Promethazine is used for allergies, motion sickness and vertigo, and for short term insomnia in adults. It also has other licensed uses depending on the formulation.
- For adults and children aged 10 years and over, the usual Phenergan 25mg tablet dose for preventing travel sickness is 25mg the night before the journey. Some promethazine products can instead be taken 1 to 2 hours before a short journey, so check the instructions for the product you have.
- There is no single official onset time in minutes for Phenergan, so be cautious about websites giving an exact figure.
- Promethazine can have effects lasting for up to 12 hours, so drowsiness can continue after the journey.
- Phenergan should not be given to children under 6 years of age.
- It should be avoided if you are taking an MAOI antidepressant or have taken one within the previous 14 days.
- Do not drive or cycle if Phenergan makes you sleepy, dizzy or affects your concentration.
How Phenergan works for motion sickness
Phenergan for motion sickness, Phenergan motion sickness, promethazine for motion sickness and travel sickness Phenergan all refer to the same basic use of the medicine.
Motion sickness happens when the signals from your eyes, inner ear and other parts of your body do not match. For example, on a boat, your inner ear can detect movement while your eyes are looking at the inside of a cabin that appears to be still. Your brain has to deal with these conflicting signals, which can lead to nausea and vomiting.
Promethazine is a sedating antihistamine. It blocks histamine H1 receptors and also has anticholinergic effects. These actions can help reduce the nausea and vomiting linked with motion sickness.
Timing is important because promethazine is generally used before travel when it is being taken to prevent motion sickness. If you are already vomiting, keeping an oral medicine down can also become more difficult.
How to take Phenergan for travel sickness
The exact instructions depend on the product you are taking. For Phenergan 25mg tablets, the product information gives the following dose for adults and children over 10 years of age:
| Situation | Recognised approach |
|---|---|
| Prevention before a journey | 25mg the night before the journey |
| If another dose is needed | A further 25mg may be taken after 6 to 8 hours, according to the product instructions |
| Short journey | Some promethazine products can be taken 1 to 2 hours before travelling, so check the specific packaging |
| Children aged 6 to 10 | Phenergan Elixir is recommended rather than the 25mg tablets for travel sickness |
The night before option and the 1 to 2 hour option are not instructions to take both doses together. They apply to different promethazine products, so check the leaflet that comes with your medicine.
If you forget a dose or are unsure when another dose is due, ask a pharmacist. Do not take extra doses simply because you are still travelling. Never exceed the recommended dose. (NHS)
Phenergan for different journeys
The medicine may be the same, but a few simple changes can make travel sickness easier to manage.
| Journey | What may help alongside the medicine |
|---|---|
| Car | Sit where you can see the road ahead, look towards the horizon and get some fresh air if possible |
| Sea and ferry | Try to stay in a part of the boat where movement feels less noticeable and look towards the horizon |
| Air | If turbulence makes you feel sick, looking at a fixed point and getting some fresh air from the overhead vent may help |
| Coach | Sit towards the front if possible, look outside rather than reading and avoid screens if they make you feel worse |
| Train | Look out of the window or towards the direction of travel if that feels more comfortable |
Sea travel can be particularly difficult for people who are prone to motion sickness because the movement can continue for several hours. If you are planning a long crossing, it is worth discussing the timing of your medicine with a pharmacist before you travel.
Phenergan can be an option for motion sickness, including sea sickness, but it can also make you sleepy. Think about this before taking it, particularly if you need to stay alert during the journey.
Does Phenergan help nausea
It depends on what is causing the nausea.
Promethazine is used for nausea and vomiting associated with motion sickness and vertigo. It is therefore reasonable to use Phenergan for these specific causes when it is suitable for you.
If your nausea is caused by something else, such as a stomach infection, migraine, pregnancy or a medicine you are taking, Phenergan may not be the right treatment. It is better to work out what is causing the nausea rather than simply trying to suppress the symptom.
If you are repeatedly feeling sick, cannot keep fluids down, have severe pain, or have nausea without an obvious cause, speak to a pharmacist or doctor.
Phenergan can cause side effects including drowsiness, dizziness, blurred vision, dry mouth and constipation. More serious reactions are possible but are much less common. It can also interact with alcohol and other medicines that cause drowsiness, so check with a pharmacist if you take other medicines. (NHS)
Phenergan for vertigo and dizziness
This needs a little more explanation because vertigo and general dizziness are not quite the same thing.
Promethazine is used for vomiting and feeling sick caused by vertigo. However, it does not treat every cause of dizziness, and the cause of the vertigo still matters.
Vertigo usually means a spinning or movement sensation. It can happen because of problems affecting the inner ear or balance system. Other medicines may be more appropriate depending on the cause. Cinnarizine and prochlorperazine, for example, are used in some situations involving vertigo, while betahistine is used for Ménière's disease.
If you have new or unexplained vertigo, speak to a GP or pharmacist rather than choosing a medicine based only on the symptom. Vertigo with symptoms such as sudden hearing loss, severe headache, double vision, weakness or difficulty speaking needs urgent medical assessment.
How long it lasts, and what to expect
Promethazine can have effects lasting for up to 12 hours. There is no single official onset time published for Phenergan, so be cautious about claims that it always starts working within a particular number of minutes.
Drowsiness is a very common side effect. This can be useful to know before a journey because you may still feel sleepy after you arrive.
Other recognised side effects include dry mouth, blurred vision, constipation and difficulty passing urine. Some people can also experience restlessness, unusual movements or other nervous system effects.
Avoid alcohol while taking Phenergan because it can increase the sedating effects of promethazine. You should also check with a pharmacist before taking it with other medicines that cause drowsiness or affect the nervous system.
Promethazine can also affect heart rhythm in some people, particularly when other risk factors or medicines that prolong the QT interval are involved. If you have a heart condition or take medicines that can affect heart rhythm, check with a pharmacist or doctor before using it. (medicines.org.uk)
Phenergan for flying
Motion sickness is less common on a plane than on some other types of transport, but turbulence can still make some people feel sick.
If you are prone to travel sickness when flying, the same basic approach applies: take the medicine according to the instructions for your particular product and allow enough time for it to work before the journey.
If the real problem is fear or anxiety about flying, Phenergan is not licensed to treat anxiety. It may make you sleepy, but that is not the same as treating anxiety. If fear of flying is stopping you from travelling or causing significant distress, speak to a GP. Some airlines also offer fear of flying courses.
Which product is which
Promethazine is available in more than one UK product, and the products do not all contain the same salt.
| Product | Contains | Main use |
|---|---|---|
| Phenergan tablets and elixir | Promethazine hydrochloride | Allergy, motion sickness, vertigo and other licensed uses |
| Avomine | Promethazine teoclate | Travel sickness |
| Stugeron | Cinnarizine | Motion sickness and vertigo |
| Kwells | Hyoscine hydrobromide | Motion sickness |
These medicines work differently and can have different side effects. For example, hyoscine can cause a dry mouth and blurred vision, while promethazine commonly causes drowsiness. A pharmacist can help you choose an option based on your journey, other medicines and any health conditions you have.
Non medicine measures can also help. Look towards the horizon, avoid reading or using screens if they make you feel worse, get some fresh air when possible, and choose a light meal rather than travelling on a very full stomach.
And if you searched for "finnegan for nausea", you may have meant Phenergan. Finnegan is a common misspelling rather than a different travel sickness medicine.
Who should not take it
Phenergan is not suitable for everyone. It should not be taken by:
- Anyone with a known allergy to promethazine, other phenothiazines or any of the ingredients in the medicine.
- Anyone who is in a coma or has central nervous system depression from any cause.
- Children under 6 years of age when using the oral Phenergan products.
- Anyone taking an MAOI antidepressant or who has taken one within the previous 14 days.
Some health conditions do not necessarily mean you cannot take Phenergan, but they may mean that extra care is needed. These include epilepsy, asthma and other lung conditions, severe coronary artery disease, liver or kidney problems, Parkinson's disease, an underactive thyroid, heart failure, myasthenia gravis, an enlarged prostate and narrow angle glaucoma.
Older adults may also be more sensitive to the effects of promethazine. Tell your pharmacist about any health conditions you have and all the medicines you take, including medicines bought without a prescription. (medicines.org.uk)
When to get medical advice
Speak to a pharmacist or doctor if:
- Vomiting continues and you cannot keep fluids down.
- You have nausea or vomiting that is not related to travel and you do not know what is causing it.
- You develop new or unexplained vertigo.
- Vertigo occurs with sudden hearing loss, severe headache, double vision, weakness or difficulty speaking. These symptoms need urgent medical assessment.
- You develop severe restlessness, agitation or an inability to keep still after taking promethazine.
- You remain very drowsy the following day and it is affecting your normal activities or ability to drive.
- You have difficulty passing urine or develop severe constipation.
- You have unusual muscle movements, stiffness, tremors or other worrying symptoms.
- You develop difficulty breathing, swelling of the face, lips, tongue or throat, or another sign of a serious allergic reaction. Seek emergency medical help if this happens.
Suspected side effects can be reported through the MHRA Yellow Card Scheme. These reports help regulators monitor the safety of medicines after they are licensed.
Buying it, and what it costs
Promethazine is available as a pharmacy medicine in the UK, so you can ask a pharmacist for advice before buying it. The pharmacist can check whether it is suitable for your journey and whether it could interact with any other medicines you take.
| Product | Pack | Price |
|---|---|---|
| Phenergan 25mg tablets | 56 tablets | £14.99 |
| Phenergan Elixir 5mg/5ml | 100ml oral solution | £14.49 |
Prices were correct at the time of writing, so the live product pages should be checked for current pricing and availability.
If you are travelling, it is worth sorting out your medicine before you leave rather than waiting until you are at the airport or port. This gives you time to check the dose, ask questions and make sure the medicine is suitable for you.
Other treatments available from EveryDayMeds
Alongside travel and allergy medicines, the pharmacy supplies prescription treatments for other conditions. If you are looking for something unrelated, you can browse weight loss treatments or read about Mounjaro treatment, both supplied only after an independent prescriber review. These are separate services and are listed here for navigation rather than because they relate to travel sickness.
Medical Disclaimer
This page provides general information about a pharmacy medicine available in the UK. It is not medical advice, a diagnosis or a substitute for advice from a pharmacist, GP or another qualified healthcare professional who knows your medical history. EveryDayMeds is not the manufacturer of Phenergan.
No individual dose is recommended on this page. Timing is explained in general terms to help you understand how promethazine may be used for travel sickness. Always follow the instructions supplied with your particular medicine, including the packaging and patient information leaflet. Do not exceed the stated dose, change the dosing schedule yourself or give an adult product to a child.
Nausea and vertigo can have many different causes. This page does not attempt to diagnose the reason for your symptoms. If you have unexplained or persistent nausea, new vertigo or symptoms that are getting worse, speak to a healthcare professional rather than relying on self treatment.
Suspected side effects can be reported through the MHRA Yellow Card Scheme. Seek urgent medical help if you develop difficulty breathing, swelling of the face, lips, tongue or throat, or another sudden and severe reaction.
