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What does it do?

Thiamine (also known as vitamin B1) increases the amount of vitamin B1 in your body.

Before you start

  • Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.

How should you take it?

Take thiamine regularly as directed with a glass of water.

What if you forget a dose?

Take the missed dose as soon as possible. If it is close to the time for your next dose, skip the missed dose and carry on as normal. Do not take two doses at the same time.

Can you take other medicines?

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

  • supplements that also contain thiamine (e.g. Centrum®)

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

What side effects might you notice?

Thiamine is unlikely to cause any side effects. If you notice any symptoms you are concerned about, discuss them with your doctor or pharmacist.


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

Prepared by the MyMedicines Committee at Christchurch Hospital, Te Whatu Ora - Waitaha, New Zealand. March 2023

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 Te Whatu Ora – Waitaha. 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