Thiamine (Vitamin B1)

Thiamine (vitamin B₁) is used as a dietary supplement when the amount of thiamine in the diet is not enough. People most at risk for thiamine deficiency are older adults, those who are dependent on alcohol, or who have HIV/AIDS, diabetes, malabsorption syndrome (problems absorbing food), or have had bariatric surgery (an operation that helps you lose weight by making changes to your digestive system). Thiamine is used to treat beriberi (tingling and numbness in feet and hands, muscle loss, and poor reflexes caused by a lack of thiamine in the diet) and to treat and prevent Wernicke-Korsakoff syndrome (tingling and numbness in hands and feet, memory loss, confusion caused by a lack of thiamine in the diet). Thiamine is in a class of medications called vitamins. It is needed by the body to turn foods into energy, which is important for the growth, development, and function of cells.

Thiamine comes as a tablet, capsule, and solution (liquid drops) to take by mouth. It is usually taken once to three times a day depending on the preparation, your age, and your medical condition(s). Thiamine is available without a prescription, but your doctor may prescribe thiamine to treat certain conditions. Follow the directions on your product label or doctor's instructions carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take thiamine exactly as directed. Do not take more or less of it or take it more often than recommended by your doctor.

Thiamine supplements are available alone and in combination with other vitamins.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking thiamine,

• tell your doctor and pharmacist if you are allergic to thiamine, any other medications, or any of the ingredients in thiamine products. Ask your pharmacist for a list of the ingredients.
• tell your doctor if you drink alcohol or if you have problems absorbing food or if you are receiving dialysis treatments.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking thiamine, call your doctor.

Unless your doctor tells you otherwise, continue your normal diet.

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Thiamine may cause side effects. Tell your doctor if either of these symptoms is severe or does not go away:

• flushing
• hives
• itching
• weakness
• sweating
• nausea
• restlessness

Thiamine may cause other side effects. Call your doctor if you have any unusual problems while taking this vitamin.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (https://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location — one that is up and away and out of their sight and reach. https://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (https://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your response to thiamine.

Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking thiamine.

Ask your pharmacist any questions you have about thiamine.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.