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Overview: Vitamin K is usually given as an injection by a health care provider to reduce bleeding risk and treat certain blood clotting problems. The most common side effects of vitamin K are pain, itching, swelling, or redness near the injection site (where the needle went in). Serious side effects are less common but can include severe allergic reactions. Tell your health care provider right away if you have trouble breathing, your heart is racing, or you feel dizzy after using vitamin K.

Uses

What is vitamin K (injection) used for?

Vitamin K is commonly used to reduce bleeding risk or treat blood clotting problems in newborn babies.

Vitamin K is also used to reduce bleeding risk and correct certain blood clotting problems. These blood clotting problems can be from any of the following.

  • Medicines that block the activity of vitamin K in your body, such as warfarin, which is a blood thinner
  • Other medicines or health conditions that affect your body’s ability to absorb, process, or use vitamin K

Vitamin K may also be used for other conditions as determined by your health care provider.

How does vitamin K (injection) work (mechanism of action)?

Newborn babies have low levels of vitamin K. Giving vitamin K to all newborns can help to reduce the risk of serious bleeding after birth.

Your body uses vitamin K to make certain proteins, called clotting factors. Clotting factors help your body form blood clots. Forming a blood clot is your body’s way to stop bleeding and heal from wounds or injuries.

People with certain health problems, or people who are taking certain medicines, may not absorb enough vitamin K from foods. Giving them vitamin K can help to increase vitamin K levels.

Warfarin, a blood thinner, works by directly blocking vitamin K in the body. Some people use this medicine to reduce the risk of dangerous blood clots. In people who take too much warfarin, or who need to have an urgent procedure or surgery, taking vitamin K can help to reverse the effects of warfarin.

How is vitamin K (injection) supplied (dosage forms)?

Vitamin K is available in an injectable form that is given by a health care provider.

Vitamin K is also available in a form that you take by mouth. See: Vitamin K oral (phytonadione)

How should I store vitamin K (injection)?

Vitamin K is usually given by a health care provider in a hospital or clinic. If you will store vitamin K at home, follow the instructions given by your health care provider.

Side Effects

What are the most common side effects of vitamin K (injection)?

The most common side effects of vitamin K are pain, itching, swelling, or redness near the injection site. Tell your health care provider if you have any of these side effects that bother you.

There may be other side effects of vitamin K that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of vitamin K (injection)?

While less common, the most serious side effects of vitamin K are described below, along with what to do if they happen.

Severe Allergic Reactions. Vitamin K may cause allergic reactions, which can be serious. Stop using vitamin K and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown, depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Warnings & Precautions

Who should not use vitamin K (injection)?

Allergies to Ingredients. People who are allergic to any of the following should not use vitamin K.

  • Aqua-Mephyton
  • Mephyton
  • Phytonadione
  • Vitamin K
  • Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific vitamin K products they stock.

What should I know about vitamin K (injection) before using it?

Vitamin K is usually given as a shot by a health care provider in a hospital or clinic.

If you store vitamin K at home, do not share it with other people, even if they have the same condition as you. It may harm them. Also, keep vitamin K out of the reach of children.

What should I tell my health care provider before using vitamin K (injection)?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if vitamin K is right for you.

In particular, make sure that you discuss any of the following.

Kidney Problems. Vitamin K has aluminum in it. Your body gets rid of aluminum through your pee (urine). If you use vitamin K long-term and have kidney problems, it is possible that you could build up too much aluminum in your body. Too much aluminum can lead to bone and central nervous system (CNS) problems. Tell your health care provider if you have any kidney problems. If there is a concern about the health of your kidneys, your health care provider may do tests to see if they are working well enough for you to use this medicine.

Liver Problems. If you have blood clotting problems because your liver is not working as well as it should be, vitamin K will not fix this. Tell your health care provider if you have any liver problems. If there is a concern about the health of your liver, your health care provider may do tests to see how well it is working.

Other Medicines and Supplements. Vitamin K may interact with other medicines and supplements. Before using vitamin K, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how vitamin K could affect pregnancy or harm an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant. Your health care provider will let you know if you should use vitamin K while you are pregnant or trying to get pregnant.

Breastfeeding. Small amounts of vitamin K pass into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should use vitamin K while breastfeeding.

Interactions

Does vitamin K (injection) interact with foods or drinks?

There are no known interactions between vitamin K and foods or drinks.

It is unknown if drinking alcohol will affect vitamin K. Vitamin K is used to reduce bleeding risk from certain blood clotting problems. Alcohol can increase your risk of bleeding. It is best to limit the amount of alcohol you drink.

Does vitamin K (injection) interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before using vitamin K.

  • An antibiotic, which is a medicine used for bacterial infections
  • Warfarin, which is a blood thinner

This may not be a complete list of medicines that can interact with vitamin K. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much vitamin K (injection)?

If you or someone else has used too much vitamin K, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of vitamin K (injection)?

Vitamin K is usually given by a health care provider in a hospital or clinic. Your health care provider will make sure you are receiving it as scheduled.