Promethazine comes in 10mg, 20mg and 25mg tablets. Your dose depends on why you’re taking it:
- short-term insomnia – you’ll usually take 20mg to 50mg at night
- hay fever – you’ll usually take from 10mg twice a day to 20mg, 3 times a day
- hives – you’ll usually take from 10mg twice a day to 20mg 3 times a day
- preventing motion sickness – you’ll usually take 25mg 1 to 2 hours before a short journey or 25mg the night before a long journey
- treating motion sickness – take 25mg as soon as possible and 25mg the same evening, followed by 25mg the following evening (if you need it)
- vertigo – the dose can vary from 25mg a day to 25mg 4 times a day
If you’re taking liquid which contains 5mg of promethazine in 5ml, follow the instructions that come with the medicine for how much to take.
Doses are lower for children. Your doctor will use your child’s age to work out the right dose.
Promethazine mixed with other medicines
Promethazine can come mixed with other medicines, such as paracetamol. This is usually used to treat cough and cold symptoms. Your dose will depend on the type of medicine you’re taking.Promethazine Dosage and Strength
Check the instructions on the packaging carefully, or ask your pharmacist or doctor if you’re unsure.
How to take it
You can take promethazine tablets, capsules and liquid with or without food.
How to take tablets and capsules
Always take your promethazine tablets or capsules with a drink of water. Swallow them whole. Do not chew them.