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What does it do?

Promethazine is used to treat and prevent allergic conditions such as hayfever and skin rashes. It is also used for nausea and vomiting, or to help you sleep.

How should you take it?

Take promethazine as directed.
Take the tablets with a glass of water.
Measure the liquid carefully with an oral syringe or measuring spoon.

What if you forget a dose?

If you take promethazine regularly and it is nearly time for your next dose, skip the missed dose and take your next dose at the usual time. Otherwise, take the missed dose as soon as you remember. Do not take two doses at the same time.

Can you take other medicines?

Some medicines available without a prescription may react with promethazine including:

  • other antihistamines (may be in anti-allergy, anti-nausea and cough/cold medicines)
  • other medicines that may cause drowsiness (e.g. pain-killers, anti-nausea and cough/cold medicines – ask your pharmacist)
  • antacids (e.g. Mylanta®)

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products (e.g. valerian) or recreational drugs.

What side effects might you notice?

Side EffectsRecommended action

Fast or irregular heartbeat, fainting

Tell your doctor immediately

Unusual behaviour or thinking, loss of co-ordination

Tell your doctor

Drowsiness, dizziness, headache

Restlessness

Dry mouth

Changes in vision

Increased sensitivity to sunlight

Stomach upset

Tell your doctor if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.

Other information:

  • Tell your doctor if you have liver, kidney, heart, lung, gut, prostate, bladder or eye (e.g. glaucoma) problems, or if you have ever had a seizure.
  • Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
  • Your doctor may do a heart test (ECG) before you start and while you are taking promethazine.
  • Promethazine may make you dizzy or sleepy and make it dangerous to drive, operate machinery or do other activities that require you to be alert. Limit alcohol intake because it can increase these effects.
  • Promethazine should not be used in children younger than 2 years of age unless prescribed by a specialist.
  • Children are more likely to experience side effects with promethazine than adults - discuss with your pharmacist or doctor.
  • Do not take indigestion remedies, iron or calcium preparations within 2 hours of taking promethazine.
  • Protect yourself from too much sunlight while being treated with promethazine. Always cover up and apply a thick layer of broad spectrum sunscreen (at least SPF 30) when outside. Do not use sunbeds.

This leaflet contains important, but not all, information about this medicine.

Prepared by the PILs Committee at Christchurch Hospital, Canterbury District Health Board, New Zealand. January 2017

For more general information about this sheet and its contents, see: What does a My Medicines sheet cover?

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About My Medicines

My Medicines Patient Information Leaflets (PILs) contain important, but not all, information about the medicines they describe.

For more information about the sheets, see: What does a My Medicines sheet cover?

My Medicines is developed by a team at the Canterbury District Health Board. Our team is made up of doctors, pharmacists, and a non-medical person to help us keep to plain language. We also discuss our information with specialist health professionals or groups when needed