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Promethazine Hydrochloride

Phenergan is a drug used to relieve nausea. It belongs to a category of tablets called phenothiazines, which are a type of antihistamine.

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PLEASE NOTE: This treatment is not available through our online pharmacy service. This page is for information only. If you are experiencing any of the symptoms related to the condition(s) this medication treats, we strongly recommend that you see your GP in person.

This content was reviewed by a clinician on

30 June 2021
dr daniel

Dr Daniel Atkinson

(GP Clinical Lead - GMC No. 4624794) 30 June 2021
Product information

Phenergan is a medication used to alleviate feelings of nausea, such as those experienced during travel sickness. It contains an agent called promethazine, which is a type of drug called a phenothiazine. This works in the body to reduce the effect of an inflammatory chemical called histamine, which is released by the immune system. The dose you use will usually depend on the type of nausea it is being used to treat. In the UK, Phenergan is marketed by Sanofi.

  1. Eases feelings of sickness
  2. Can also alleviate allergies
  3. Simple tablet treatment

The feeling of sickness, or urge to be sick, is referred to in medical terms as nausea, and is often succeeded by actual sickness, or vomiting. There are a number of reasons why someone might experience nausea, and the treatment method for the condition may vary according to the cause.

In the body, it is an area of the brain called the ‘vomiting centre’ which sends signals to the stomach and instigates the muscle spasms that cause sickness. The vomiting centre kicks into action when it receives confusing or irritating stimulus from other parts of the body.

For example, in motion sickness, it is the contradictory nature of sensory information which provides the basis for this response. While the eyes may perceive a stationary environment, such as on board a plane or a ship, the balancing system in the ear may detect movement. This then causes the vomiting centre to become active, sending signals to the stomach and causing nausea.

Sometimes, the vomiting centre can become irritated by foreign elements in other parts of the body. This might be the presence of a toxin in the stomach, such as with food poisoning, or a chemical in the blood, for instance during chemotherapy treatment. On occasion, such as during immune response or a migraine, the body releases substances of its own which can cause feelings of sickness.

The way Phenergan works is to neutralise the effects of histamine in the brain. Its functioning ingredient, promethazine, works by dulling the sensitivity of histamine receptors in the vomiting centre. This prevents the vomiting centre from becoming activated by inflammatory stimulus, thereby stopping nausea as a result.

You can buy Phenergan from our UK pharmacy with just a few clicks. Select your product and take our simple questionnaire. Every order made through our site is checked by a practising doctor prior to being issued, to help protect your safety and well-being. Our UK-based pharmacy ships all orders by secure 24-hour delivery. in most cases, you’ll receive your treatment the very next working day.

Page last reviewed:  30/06/2021


Following the instructions given by your prescriber is essential in getting the most out of your treatment and reducing the possibility of side effects. It is also important to read the patient information leaflet carefully prior to use.

  1. Use as directed by your doctor.
  2. For travel sickness, this may be one tablet taken the evening before your journey; and another taken every 6-8 hours that follow for the duration of travel.
  3. For other instances of sickness, the dose may be one tablet taken at night, followed by one more every 6-8 hours for a period specified by your doctor.
  4. The directions required for the treatment of allergies or other conditions may differ from those listed above.
  5. It should not be taken for a period longer than seven days. If symptoms persist after this, you should speak to your doctor, as they may wish to issue alternative forms of treatment.
  6. Never take more than the amount prescribed for you by your practitioner.
  7. If you forget to take it, do not double up on your next dose. Simply take it when you remember, and carry on the course as normal.

This is not a complete account of the directions you will need to follow when using this product. Refer to the more detailed instructions provided in the leaflet before use.

Download Phenergan patient information leaflet

Page last reviewed:  30/06/2021
Please read the patient information leaflet for this medicine fully before use:

Phenergan (Promethazine) 25mg

Side effects & Warnings

Side effects

Inform your doctor immediately if you notice any of the following side effects: liver problems such as jaundice; muscle stiffness or shaking; uncontrollable muscle movements; palpitations; tiredness or other signs of anaemia; or anything which may indicate an allergic reaction. Refer to the patient information leaflet to find out more about what these signs may look like.

You should also notify your pharmacist or doctor if you notice any of the following side effects, particularly if they become serious or cause you to become concerned: dry mouth; blurred vision; the inability to pass urine; drowsiness; tiredness; disorientation; nightmares; headaches; feeling restless; loss of appetite; indigestion; feeling dizzy; confusion; or photosensitivity.

More detailed information on side effects can be found in the provided leaflet.

Taking it with other medicines

Let your prescriber know when filling our medical survey if you are using other treatments, as some, such as the following, may cause interactions with this product: monoamine oxidase inhibitors (let your prescriber know if you have used these at any point in the last two weeks); anticholinergic medicines; antidepressants; drugs to help with sleep or relaxation such as diazepam or zolpidem; or aspirin.

Conditions to look out for

This treatment should not be used in cases where the patient is: unconscious; taking monoamine oxidase inhibitors; has severe headaches, dizziness or is drowsy; or allergic to this or any similar types of drug.

It may also not be suitable for those who have the following, or require administration with particular care: heart problems; difficulty breathing; asthma; bronchitis; epilepsy; liver or kidney problems; a stomach obstruction; difficulty urinating; lactose intolerance; hearing problems; or narrow angle glaucoma.

Pregnancy and breastfeeding

Check with your doctor before using the medication if you are pregnant or trying to conceive.

Phenergan must not be taken within two weeks prior to giving birth.

Do not take this medication if you are breastfeeding.

Driving and using machinery

Drowsiness may occur in those using Phenergan. Wait until you know for certain how this treatment will affect you before attempting to drive or use machines.

Food, drink and alcohol

Alcohol should not be consumed during use of this treatment.

Lactose intolerance

Phenergan contains lactose. Let your doctor know during consultation if have you any intolerance to sugars.

Page last reviewed:  30/06/2021
Please read the patient information leaflet for this medicine fully before use:

Phenergan (Promethazine) 25mg


Can I still drink alcohol?

No. The consumption of alcohol may have an adverse effect on the function of this treatment, and should therefore be avoided.

Will I still be able to drive?

Yes, but only if you experience no side effects which may make doing so dangerous. If you do notice any potentially distracting side effects or anything which might harm your judgment or coordination, do not drive and let your doctor know.

Can I use this medicine while pregnant?

It is not suitable for use during the last two weeks of pregnancy or during breastfeeding. If you are pregnant, let your doctor know before using this treatment.

How do I store it?

Make sure it is kept in a safe place below 30°C and away from children.

Am I allergic to anything in the medicine?

This item contains the following ingredients: promethazine hydrochloride, lactose, maize starch, povidone, magnesium stearate, polyethylene glycol, Opaspray (contains titanium dioxide-E171, hypromellose-E464 and indigo carmine aluminium lake blue-E132) and hypromellose.

Do not use the treatment if you are allergic to or unable to tolerate any of the above constituents.

Is it available over-the-counter?

To buy Phenergan from any online pharmacy, you will require a prescription. This can be obtained via our simple consultation service, which is staffed by registered practitioners.

Is it right for me?

It doesn’t take long to find out. Complete our questionnaire today, and your responses will be assessed by a qualified physician. Our doctor will only issue a prescription for you medication if it is safe for you to use. Shipping on all items is made from our UK-based pharmacy by secure 24-hour courier, so that you can begin using your treatment the following working day.

Page last reviewed:  30/06/2021 is rated 4.9 out of 5 by 3209 customers on TrustPilot!
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