Vitamin B1 is also known as thiamine. Vitamin B1 is found in foods such as cereals, whole grains, meat, nuts, beans, and peas. Vitamin B1 is important in the breakdown of carbohydrates from foods into products needed by the body.

Thiamine is used to treat or prevent vitamin B1 deficiency. Thiamine injection is used to treat beriberi, a serious condition caused by prolonged lack of vitamin B1.

Thiamine taken by mouth (oral) is available without a prescription. Injectable thiamine must be given by a healthcare professional.

Thiamine may also be used for purposes not listed in this medication guide.

You should not use thiamine if you have ever had an allergic reaction to it.

Ask a doctor or pharmacist before taking thiamine if you have any medical conditions, if you take other medications or herbal products, or if you are allergic to any drugs or foods.

Before you receive injectable thiamine, tell your doctor if you have kidney disease.

Thiamine is only part of a complete program of treatment that may also include a special diet. It is very important to follow the diet plan created for you by your doctor or nutrition counselor. You should become very familiar with the list of foods you should eat or avoid to help control your condition.

Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Injectable thiamine is injected into a muscle. You may be shown how to use injections at home. Do not self-inject this medicine if you do not fully understand how to give the injection and properly dispose of used needles and syringes.

Do not use the injectable medication if it has changed colors or has particles in it. Call your doctor for a new prescription.

The recommended dietary allowance of thiamine increases with age. Follow your healthcare provider's instructions. You may also consult the National Academy of Sciences "Dietary Reference Intake" or the U.S. Department of Agriculture's "Dietary Reference Intake" (formerly "Recommended Daily Allowances" or RDA) listings for more information.

Thiamine is only part of a complete program of treatment that may also include a special diet. It is very important to follow the diet plan created for you by your doctor or nutrition counselor. You should become very familiar with the list of foods you should eat or avoid to help control your condition.

Store at room temperature away from moisture, heat, and light.

You should not use thiamine if you have ever had an allergic reaction to it.

Ask a doctor or pharmacist if it is safe for you to take Vitamin B1 if:

• you have any other medical conditions;

• you take other medications or herbal products; or

• you are allergic to any drugs or foods.

To make sure you can safely receive injectable thiamine, tell your doctor if you have kidney disease.

Thiamine is not expected to harm an unborn baby. Your thiamine dose needs may be different during pregnancy. Do not take thiamine without medical advice if you are pregnant or plan to become pregnant.

It is not known whether thiamine passes into breast milk. Your dose needs may be different while you are nursing. Do not take thiamine without medical advice if you are breast-feeding a baby.

Use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have a serious side effect such as:

• blue colored lips;

• chest pain, feeling short of breath;

• black, bloody, or tarry stools; or

• coughing up blood or vomit that looks like coffee grounds.

Less serious side effects may include:

• nausea, tight feeling in your throat;

• sweating, feeling warm;

• mild rash or itching;

• feeling restless; or

• tenderness or a hard lump where a thiamine injection was given.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

There may be other drugs that can interact with thiamine. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.