Phenergan is an anti-nausea medication that works to combat the symptoms of nausea and motion sickness. It’s often used for the effects of day-to-day issues such as travel sickness, but in rarer cases it can also be used to treat the aftereffects of surgery, like vomiting and pain, that can be felt after you’ve had an operation.
Phenergan’s active ingredient - promethazine hydrochloride, is a type of drug called a phenothiazine. It works by blocking the natural chemical: histamine, that your body produces during an allergic reaction. This means that as well as being an effective treatment against nausea, Phenergan is also used for reducing allergy symptoms.
How does Phenergan work?
Phenergan works by lowering the effects of histamine in the brain, changing the way the chemicals in your brain take action. Its active ingredient, promethazine, works by dulling the sensitivity of histamine receptors in the part of your brain associated with vomiting.
Promethazine blocks histamine receptors without actually stopping the release of histamine. This stops the vomiting centre from becoming activated by inflammatory stimulus, and so helps to stop nausea and motion sickness.
What doses of Phenergan are there?
Phenergan comes in doses of 10mg, 20mg and 25mg doses for adults, to be taken two to three times per day. The dosage will depend on the type and strength of your nausea. You should always refer to the patient information leaflet for details.
How to take Phenergan
You should take Phenergan as instructed by your clinician, and in line with your patient information leaflet. If you’re unsure, you can always talk to our clinician for help.
The dose you’ll take will depend on the reason that you’re taking Phenergan (whether it’s for nausea and vomiting, allergies, or as a sedative). To take Phenergan, you must:
Take the medicine orally.
Not take it for more than seven days. If your symptoms aren’t better after this period of time you should let your clinician know.
Only follow your clinician for dosage guidance. If you feel that the dose you’re taking isn’t right, don’t alter it yourself.
How long does it take Phenergan to work?
Phenergan is a quick and effective treatment for nausea, and the symptoms of nausea should reduce within 20 minutes of taking it. Don’t take more than the prescribed amount if your symptoms don’t feel like they’re getting better. Always remember to speak to your doctor or clinician for advice if you’re not sure about anything.
How long can I take Phenergan for?
Phenergan shouldn’t be taken for more than a period of seven days. If your symptoms haven’t gone down within the week you should talk to our clinician, who can advise you of what your next course of action could be.
What should I do if I make a mistake when taking Phenergan?
If you accidentally take more Phenergan than you’ve been advised to by your clinician, then you should seek medical help as soon as possible. Don’t take an extra dose to make up for a forgotten dose, just take it when you remember or skip that dose if it’s too close to your next one.
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Which dose of Phenergan should I use?
The dosage of Phenergan that you take will usually depend on how severe your nausea is. Once you’ve talked to us about your health, we’ll be able to advise you on which dose will be most suitable for you.
Is Phenergan similar to any other treatments?
Phenergan is a bit like other antihistamine treatments for nausea, such as Buccastem M and Cyclizine. They work in a similar ways to treat the symptoms of nausea and sickness, but they use different active ingredients, meaning that one treatment may suit you better than another, or might be more or less effective for you.
How effective is Phenergan?
Phenergan is considered to be an effective treatment against nausea in a similar way to other antihistamine medications that target nausea. Phenergan has been shown to work much more effectively than placebo.
Who is Phenergan for?
Phenergan is an effective short-term or situation-specific treatment against sickness, such as travel sickness, nausea and vomiting. It’s a short-term solution for these symptoms, and shouldn’t be used for longer than seven days.
Do I need a prescription for Phenergan?
You need to have a prescription in order to take Phenergan so that the prescriber can make sure that it’s safe for you to use. They’ll also need to assess the size of the dose you need - depending on the severity of your symptoms.
Why should I buy Phenergan online with Treated?
Ordering your treatment online with us means that you’ll benefit from the expert advice of our clinicians, who’ll help to find the best option for you. Your treatment will then be delivered to you in discreet packaging.
We’ll be in touch after you’ve received your treatment to check that it’s working as it should be, and that you’re not experiencing any unexpected side effects, so you can just concentrate on feeling better.
Zikos, T. A., Nguyen, L., Kamal, A., Fernandez-Becker, N., Regalia, K., Nandwani, M., Sonu, I., Garcia, M., Okafor, P., Neshatian, L., Grewal, D., Garcia, P., Triadafilopoulos, G., & Clarke, J. O. (2020).
Marijuana, Ondansetron, and Promethazine Are Perceived as Most Effective Treatments for Gastrointestinal Nausea. Digestive diseases and sciences, 65(11), 3280–3286.
Disclaimer: The information provided on this page is not a substitute for professional medical advice, diagnosis, or treatment. If you have any questions or concerns about your health, please talk to a doctor.
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