Phenergan (promethazine) is a sedating antihistamine that can be used for travel sickness, allergies and short term sleep problems in adults. It can cause significant drowsiness, so there are some important things to know before using it for a journey, especially if you are flying or travelling with children.
This guide explains what Phenergan is used for, when it is taken for travel sickness, what to know about flying, and who should avoid it.
What Promethazine Hydrochloride (Phenergan) Is Used For When Travelling
Phenergan contains promethazine, a type of antihistamine that can make you feel sleepy. It is used for conditions including allergies and nausea or vomiting caused by travel sickness. It can also be used for short term treatment of insomnia in adults.
Phenergan is available from pharmacies in the UK. Some forms are pharmacy medicines, so a pharmacist may need to check that it is suitable for you before you buy it.
Phenergan is not a treatment for flight anxiety. If you are nervous about flying, it is better to speak to a GP or other healthcare professional about suitable ways to manage anxiety rather than using a sedating medicine for this purpose.
Phenergan for Motion Sickness, Travel Sickness and Seasickness
Phenergan can be used to prevent and treat nausea and vomiting caused by travel sickness. Promethazine works partly by blocking the action of histamine and affecting signals involved in nausea and vomiting.
It can make you sleepy, which is one reason it may not be suitable when you need to stay fully alert during a journey.
If you are driving, working or doing anything that needs concentration, be aware that Phenergan can cause drowsiness, dizziness and blurred vision.
When to Take Phenergan for Travel Sickness
Timing matters when using Phenergan for travel sickness.
For adults and children over 10 years, the UK Phenergan tablet information recommends a 25 mg dose the night before the journey. This can be repeated after 6 to 8 hours if needed.
For children aged 6 to 10 years, Phenergan Elixir is recommended rather than the tablets for travel sickness. The recommended dose is 10 mg the night before the journey, which can be repeated after 6 to 8 hours if needed.
Phenergan must not be given to children under 6 years of age.
Always check the instructions for the specific Phenergan product you have and ask a pharmacist if you are unsure about the right dose. Do not use an adult dose for a child.
Phenergan for Flying and Sleeping on a Plane
Phenergan can cause drowsiness, and it is licensed for short term treatment of insomnia in adults. Some adults may therefore consider using it when they want to sleep during a long flight.
However, Phenergan is not specifically a medicine for sleeping on a plane. Its sedating effect can last for many hours, and you may still feel sleepy or less alert after landing.
If you take Phenergan:
- Do not drink alcohol. Alcohol can increase the sedating effects of promethazine.
- Be careful with other medicines. Other medicines that cause drowsiness can add to its effects.
- Do not drive if you feel drowsy. Phenergan can affect your alertness, reactions and ability to use machinery.
- Move around during long flights. Follow the usual advice to move your legs and get up regularly when it is safe to do so.
- Use it only as directed. Do not take more because you feel that the first dose has not worked enough.
The duration of action can be up to around 12 hours. This means a dose taken at night may still affect you the following morning.
Does Phenergan Help With Jet Lag?
Phenergan may make you feel sleepy, but it does not reset your body clock or treat the underlying cause of jet lag.
Jet lag happens when your body clock is out of step with the local time after travelling across time zones. Daylight exposure, adjusting your sleep schedule and keeping to local meal and sleep times can help your body adjust.
If you choose to use Phenergan for short term sleep problems, remember that its drowsiness can continue into the following day. It should not be treated as a cure for jet lag.
A Serious Warning About Children and Flying
This is particularly important if you are travelling with children.
Promethazine must not be given to children under 6 years of age. There is a risk of serious side effects in this age group.
Sedating medicines should also not be given to a child simply to make them sleep during a flight or journey. Promethazine can cause unusual reactions in some children, including agitation, restlessness or increased activity.
If a child aged 6 years or above has travel sickness, speak to a pharmacist or GP about the appropriate product and dose. Do not use an adult dose or give the medicine simply to make the journey easier for the adults.
How Long Does It Last, Side Effects, and How Drowsy Will You Be?
Phenergan can have a long lasting effect. Its duration of action may be up to around 12 hours, and some people may feel drowsy, dizzy or less alert during this time.
Other possible side effects include blurred vision, dry mouth, headache, restlessness and confusion. Older people may be more likely to experience confusion and other effects linked to the medicine.
If you feel drowsy or your vision is affected, do not drive or use machinery. Be especially careful when you arrive at your destination because you may still be affected by the medicine the next morning.
Tablets or Elixir for Travel?
Phenergan is available as 25 mg tablets and as Phenergan Elixir 5 mg/5 ml oral solution.
For children aged 6 to 10 years who need Phenergan for travel sickness, the UK product information recommends the elixir rather than the tablets.
For adults and children over 10 years, tablets may be more convenient for travel. The right product and dose depend on your age and reason for taking it.
If you are travelling with Phenergan, keep it in its original labelled packaging. This can also make it easier to identify the medicine and its ingredients if you need medical help while travelling.
Who Should Not Take Phenergan
Phenergan is not suitable for everyone. Do not take it if you:
- Are under 6 years old.
- Are allergic to promethazine or another ingredient in the medicine.
- Are taking an MAOI antidepressant or have stopped taking one within the last 14 days.
- Are unconscious or have severe central nervous system depression.
You should also speak to a doctor or pharmacist before taking Phenergan if you have conditions such as asthma or other breathing problems, epilepsy, liver or kidney problems, glaucoma, prostate problems or certain heart conditions.
Promethazine can cause drowsiness and its effects can be stronger when taken with other medicines that cause sedation. Alcohol should be avoided while taking Phenergan.
Phenergan should not be taken for longer than 7 days without medical advice. If your symptoms continue or become worse, speak to a doctor or pharmacist.
If you are pregnant or breastfeeding, speak to a doctor or pharmacist before taking Phenergan. The UK product information advises against breastfeeding while taking Phenergan.
Other Travel Sickness Options and Foreign Brands
Phenergan is not the only option for travel sickness. Other medicines are available, including cinnarizine and hyoscine hydrobromide.
The best option depends on factors such as your age, other medicines, health conditions and how much drowsiness you can tolerate. A pharmacist can help you choose a suitable option.
If you have seen an anti sickness medicine while travelling abroad, check the active ingredient rather than relying only on the brand name. Brand names can be different between countries, and medicines with similar names may contain different ingredients.
Diphenhydramine is another antihistamine used in some UK medicines, but it is not the same medicine as promethazine.
