Just a few questions from our Pharmacist before you checkout to make sure this medicine is safe for you.
What is Phenergan Elixir?
Phenergan Elixir is an over the counter, drowsy antihistamine that comes as a liquid solution. It contains the active ingredient promethazine hydrochloride and is an alternative for people who can’t, or prefer not to, swallow tablets whole.
What is Phenergan Elixir used for?
Promethazine can help manage a range of symptoms and conditions. Depending on why you're taking it, Phenergan Elixir may help provide relief from the following:
- hay fever and allergies
- travel sickness
- cold symptoms (like runny nose or sneezing) and irritation
- short-term insomnia in adults
How does Phenergan Elixir work?
Phenergan Elixir belongs to a group of medication known as antihistamines. Your body releases histamine in response to allergens, for example, pollen.
Histamine can release in your eyes (making them itchy), or your nose making it runny. Taking Phenergan Elixir helps relieve symptoms by blocking the action of histamine.
As well as this, Phenergan can have a sedative effect on the central nervous system, which may help reduce the symptoms of travel sickness. The calming effect may also make you feel sleepy, supporting short-term sleep issues.
How quickly does it work?
Once you’ve taken Phenergan Elixir, it should start working in as little as 1-2 hours. However, how quickly the effects are noticed varies from person to person, and whether you’re taking it on an empty stomach.
How long does it last?
After you’ve taken it, the effects of Phenergan Elixir can last for several hours, though some people may require another dose later on if they feel the effects are wearing off too soon.
How to use Phenergan Elixir
You should always read the patient information leaflet before using Phenergan Elixir.
When using Phenergan Elixir:
- Always take it by mouth.
- When taking the solution, measure out each dose with a plastic syringe or a medicine spoon.
- The dose you should take depends on age, what you’re taking it for, or what you have been advised by a pharmacist.
Phenergan Elixir shouldn’t be used for more than seven days (one week) unless you’ve been advised to do so by a healthcare professional.
If you’ve been taking Phenergan Elixir for seven days and haven’t noticed any improvement, or feel like your symptoms have worsened, speak to your doctor for further advice.
Phenergan Elixir dosage
The amount of Phenergan Elixir that you should take varies depending on what you're taking it for:
For allergies (like hay fever, rashes and hives):
- Children 6-10 years: One to two 5ml spoonfuls twice a day, with a maximum of five 5ml spoonfuls in 24 hours.
- Children over 10 years and adults: Two 5ml spoonfuls twice a day, which can be increased to a maximum of four 5ml spoonfuls three times a day.
For travel sickness:
- Children 6-10 years: Two 5ml spoonfuls the night before the journey, which may be repeated after six to eight hours if required.
- Children over 10 years and adults: Five 5ml spoonfuls the night before the journey, which may be repeated after six to eight hours if required.
If you forget to take a dose, do not take a double dose to make up for the forgotten dose. Instead, take it as soon as you remember, then carry on as before.
Side effects of Phenergan Elixir
Like all medicines, Phenergan Elixir can cause side effects, but most people use it without experiencing any serious problems.
Because it contains promethazine, a drowsy antihistamine, the most common side effect is feeling sleepy or less alert than usual. Other common side effects include:
- dizziness
- headaches
- dry mouth
Additionally, you should avoid drinking alcohol while taking Phenergan Elixir as it can increase drowsiness.
Important: Do not drive, cycle or operate machinery if this medicine makes you feel sleepy, dizzy or unable to concentrate.
When to seek medical help
Serious side effects from Phenergan Elixir are uncommon, but they can happen. Stop taking this medicine and seek urgent medical attention straight away if:
- you’re feeling confused or have blurred vision
- you have difficulty peeing
- the whites of your eyes or your skin turns yellow (jaundice)
- you are bruising or bleeding more than normal
Additionally, if you develop signs of a severe allergic reaction contact 999 immediately. Symptoms include:
- a rash
- swelling of the face, lips, tongue or throat
- difficulty breathing
Alternatives to Phenergan Elixir
If you're looking for an alternative to Phenergan Elixir, the best option will depend on the symptoms you're trying to treat.
If you don't mind taking tablets, there are several antihistamines available that may help with allergy symptoms, including generic promethazine tablets and Phenergan itself. However, for a non-drowsy tablet, look for:
If you're looking for help with travel sickness specifically, there are also alternative treatments available:
Frequently asked questions about Phenergan Elixir
Does liquid Phenergan make you sleepy?
Yes, Phenergan Elixir can make you feel sleepy. It contains promethazine hydrochloride, a drowsy antihistamine that affects the central nervous system and may cause tiredness or drowsiness.
Can I buy Phenergan liquid over the counter?
Yes, Phenergan Elixir is available over the counter from pharmacies without a prescription. However, it is not suitable for everyone, so you may be asked a few questions by a pharmacist before purchasing it to make sure it's appropriate for you.
Sources
- About promethazine (2025). NHS. [Accessed 16 July 2026]
- Who can and cannot take promethazine (2025). NHS. [Accessed 16 July 2026]
- How and when to take promethazine (2025). NHS. [Accessed 16 July 2026]
- Side effects of promethazine (2025). NHS. [Accessed 16 July 2026]
