What it is used for
- Treating and preventing thiamine (vitamin B1) deficiency
- Supporting people with heavy alcohol use, who are at high risk of deficiency
- Treating or preventing serious deficiency-related conditions affecting the brain and nerves under medical care
- Supporting nutrition in poor diet or absorption problems
How it works
Thiamine helps the body convert carbohydrates from food into energy and is essential for healthy nerve and brain function. Without enough, the nervous system and heart can be seriously affected, which replacing thiamine prevents or treats.
How it is taken
Available as tablets and as an injection given by a healthcare professional, used when deficiency is severe or absorption is poor. Oral forms can be taken with or without food. Take or receive it exactly as your doctor, pharmacist or the label directs.
No doses here on purpose. The right strength and schedule depend on you — only a doctor or pharmacist should set them. Always follow your prescription and the label.
Common side effects
- Usually very well tolerated
- Mild stomach upset (uncommon)
- Warmth or mild reaction at the injection site
Serious effects — get help
- Rarely, a serious allergic reaction with injections, including difficulty breathing or swelling
- Signs of an allergic reaction such as rash or itching
If a reaction is severe — for example trouble breathing, swelling of the face or throat, or collapse — go to the nearest emergency room now or call your local emergency number. Do not wait for an online consultation.
Interactions to watch
- Few significant interactions with oral thiamine
- Heavy alcohol use, which lowers thiamine levels and absorption
- Some water pills that increase thiamine loss
Who should take care
- Tell your clinician if you have a history of allergic reactions to vitamin injections
- People with heavy alcohol use or eating disorders may need supervised, sometimes higher, treatment
- Severe deficiency-related brain symptoms are a medical emergency and need urgent care
- Discuss use in pregnancy and breastfeeding with your clinician