promethazine

What to do if you missed your promethazine dose

Other known brand names

Avomine, Phenergan

About promethazine

Promethazine hydrochloride is an antihistamine and has anti-emetic and anticholinergic effects on the body. Promethazine is used to treat insomnia, allergies such as hay fever, symptoms of the common cold (when mixed with paracetamol, dextromethorphan or pseudoephedrine), and the prevention of travel sickness.

Promethazine is alao available as alternative brands of promethazine such as Sominex, Avoimne and Phenergan. Now Patient offers promethazine as a treatment for travel sickness only, following an online consultation with a prescribing clinician.

Key facts of promethazine

• For the treatment of motion sickness
• Take promethazine the night before a long journey or 1 or 2 hours before a short journey
• Promethazine has some common side effects which include drowsiness, headaches, and dizziness
• Do not drink alcohol when taking promethazine as this may increase the risk of side effects
• It can be dangerous if you take promethazine with certain medications like sleeping tablets. If you’re not sure if it is safe, discuss this with the prescribing clinician

Who is promethazine suitable for?

Promethazine is suitable for most adults.

Who is promethazine not suitable for?

Promethazine may not be suitable for some people. To make sure it’s safe for you, speak to the prescribing clinician before taking promethazine if you:

• Have previously had an allergic reaction to promethazine, or other phenothiazines
• Have glaucoma
• Have high blood pressure
• Have epilepsy
• Have liver, kidney or bladder problems
• Have a weak immune system (bone marrow depression)
• Have asthma, chronic obstructive pulmonary disease, or sleep apnea
• Are pregnant or trying to get pregnant. Promethazine can affect home pregnancy tests

How and where to get promethazine 25mg tablets?

Promethazine is available from a number of sources. It is available over the counter at a pharmacy.

Now Patient does not allow customers to buy promethazine directly. Our service is certified, safe and effective, and we only ever treat conditions. If you book a consultation with a prescribing clinician for the treatment of motion sickness, you can discuss if promethazine is a suitable treatment option for you.

At the end of the consultation, the clinician will decide if a treatment plan is suitable for you. If it is, the clinician will issue you with a prescription which can then be ordered, paid for and delivered directly to your chosen address by Now Patient.

Dosage and strength for promethazine for travel sickness

Promethazine is available as tablets, liquid, rectal suppositories, or as injection for intramuscular, or intravenous administration. The dosage for the tablets, solutions, and suppository is 12.5 mg to 50 mg. Promethazine is available as 25mg tablets when used for the treatment of travel sickness.

Information about how to take promethazine for travel sickness

For the prevention of motion sickness, take 25mg 1 or 2 hours before a short journey or 25mg the night before a long journey. When treating motion sickness, take 25mg immediately and 25mg the same evening, then 25mg the next day, if needed. Read the patient information leaflet supplied with your medication for further information, or speak to your healthcare provider for further medical advice.

What happens if you take too much promethazine?

If you take more than prescribed, then it can lead to some unpleasant side effects. Promethazine can cause symptoms such as respiratory depression, CNS depression, hypotension, unconsciousness, and sudden death, especially in patients under 2 years of age.

You should talk to your doctor or reach out to one of our prescribing clinicians, if you have taken too much promethazine and you experience any of the following side effects:

• Drowsiness
• An irregular heartbeat
• Breathing problems

In serious cases, you can become unconscious or have seizures or fits and may need emergency treatment in hospital.

What are the side effects of promethazine?

Side effects of promethazine are split into common and serious.

Common side effects include:

• Daytime tiredness
• Blurred vision
• Upset stomach, loss of appetite, diarrhea
• Nightmares
• Dizziness
• Headaches
• Skin sensitivity to sunlight (Use sunscreen and wear protective clothing when outdoors)
• Older adults may experience confusion, dry mouth, blurred vision, and difficulty urinating

Serious side effects include:

• Yellowing of your eyes which may be a sign of liver problems (jaundice)
• Bruising or bleeding easily
• Muscle stiffness or shaking
• Unusual face or tongue movements
• Neuroleptic malignant syndrome (a brain disorder)

If you experience any serious side effects, you should contact NHS 111.

If you experience a serious allergic reaction such as anaphylaxis with the signs shown below you should contact emergency services on 999.

• HIves
• Your lips, mouth, throat or tongue suddenly become swollen
• You’re breathing very fast or struggling to breathe (you may become very wheezy or feel like you’re choking or gasping for air)
• Your throat feels tight or you’re struggling to swallow
• Your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
• You suddenly become very confused, drowsy or dizzy
• Someone faints and cannot be woken up

Always report adverse effects to the MHRA yellow card reporting system. You can read more about this here: how and where do i report side effects of my medication

Information about taking promethazine at the same time as other medications or herbal supplements

There may be drug interactions when taking herbal supplements with promethazine, especially those that cause sleepiness, or dry mouth. Also tell your doctor if you are taking:

• Antidepressants such as monoamine oxidase inhibitors
• Opioids, such as codeine, morphine, or oxycodone
• Other drowsy antihistamines such as chlorphenamine and diphenhydramine

Also, speak with a healthcare professional before you take promethazine with any other painkillers or medicines.

How long does promethazine take to work?

Promethazine will start to work within 20 minutes and may continue to work for up to 12 hours.

Can promethazine be taken long term?

You should only take promethazine for short periods, unless your doctor says it’s ok to take it longer.

Is promethazine addictive?

Promethazine is not addictive, but do not take it for longer than advised. If you have taken promethazine for a long time and suddenly stop, you may feel dizzy or sick. Speak to your doctor before stopping promethazine if you have taken it for a long time.

Is there a herbal promethazine?

No. Herbal promethazine does not exist. If you have been marketed such a formulation, it may be fake.

Can women use promethazine when pregnant or breastfeeding?

Yes. Promethazine is not harmful to your baby. Also, if your doctor says your baby is healthy, promethazine can be used during breastfeeding.

Should I avoid any particular food or drink when taking promethazine?

You can eat and drink normally when taking promethazine However, do not drink alcohol when taking promethazine as this may increase the risk of side effects.

Alternatives to promethazine

Alternatives for the treatment of motion sickness include Phenergan, Avomine, and Scopoderm (scopolamine).

Sources

• Insomnia – NHS 
• NHS – Promethazine