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Vitamin K (Oral route, parenteral route)

Brand Names:

  • Mephyton

Dosage Forms:

  • Capsule
  • Tablet

Uses of This Medicine:

Vitamins are compounds that you must have for growth and health. They are needed in only small amounts and usually are available in the foods that you eat. Vitamin K is necessary for normal clotting of the blood.

Vitamin K is found in various foods including green leafy vegetables, meat, and dairy products. If you eat a balanced diet containing these foods, you should be getting all the vitamin K you need. Little vitamin K is lost from foods with ordinary cooking.

If you are taking anticoagulant medicine (blood thinners), the amount of vitamin K in your diet may affect how well these medicines work. Your doctor or health care professional may recommend changes in your diet to help these medicines work better.

Lack of vitamin K is rare but may lead to problems with blood clotting and increased bleeding. Your doctor may treat this by prescribing vitamin K for you.

Vitamin K is routinely given to newborn infants to prevent bleeding problems.

This medicine is available only with your doctor's prescription.

Before Using This Medicine:

If you are taking a dietary supplement without a prescription, carefully read and follow any precautions on the label. For these supplements, the following should be considered:

Allergies—

Tell your doctor if you have ever had any unusual or allergic reaction to medicines in this group or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Children—

Children may be especially sensitive to the effects of vitamin K, especially menadiol or high doses of phytonadione. This may increase the chance of side effects during treatment. Newborns, especially premature babies, may be more sensitive to these effects than older children.

Older adults—

Many medicines have not been tested in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information about the use of vitamin K in the elderly.

Pregnancy—

Vitamin K has not been reported to cause birth defects or other problems in humans. However, the use of vitamin K supplements during pregnancy is not recommended because it has been reported to cause jaundice and other problems in the baby.

Breast-feeding—

Vitamin K taken by the mother has not been reported to cause problems in nursing babies. You should check with your doctor if you are giving your baby an unfortified formula. In that case, the baby must get the vitamins needed some other way.

Other medicines—

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Other interactions—

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other medical problems—

The presence of other medical problems may affect the use of dietary supplements in this class. Make sure you tell your doctor if you have any other medical problems, especially:

  • Cystic fibrosis or other diseases affecting the pancreas or
  • Diarrhea (prolonged) or
  • Gallbladder disease or
  • Intestinal problems—These conditions may interfere with absorption of vitamin K into the body when it is taken by mouth; higher doses may be needed, or the medicine may have to be injected.
  • Glucose-6-phosphate dehydrogenase (G6PD) deficiency—The chance of side effects may be increased, especially with menadiol.
  • Liver disease—The chance of unwanted effects may be increased.

Proper Use of This Medicine:

Take this medicine only as directed by your doctor. Do not take more or less of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so may cause serious unwanted effects, such as blood clotting problems.

Dosing—

The dose medicines in this class will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of these medicines. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets):
    • For problems with blood clotting or increased bleeding, or for dietary supplementation:
      • Adults and children—The usual dose is 5 to 10 milligrams (mg) a day.
  • For injection dosage form:
    • For problems with blood clotting or increased bleeding, or for dietary supplementation:
      • Adults and teenagers—The usual dose is 5 to 15 mg, injected into a muscle or under the skin, one or two times a day.
      • Children—The usual dose is 5 to 10 mg, injected into a muscle or under the skin, one or two times a day.
  • For oral dosage form (tablets):
    • For problems with blood clotting or increased bleeding:
      • Adults and teenagers—The usual dose is 2.5 to 25 milligrams (mg), rarely up to 50 mg. The dose may be repeated, if needed.
      • Children—Use is not recommended.
  • For injection dosage form:
    • For problems with blood clotting or increased bleeding:
      • Adults and teenagers—The usual dose is 2.5 to 25 mg, rarely up to 50 mg, injected under the skin. The dose may be repeated, if needed.
    • For prevention of bleeding in newborns:
      • The usual dose is 0.5 to 1 mg, injected into a muscle or under the skin, right after delivery. The dose may be repeated after six to eight hours, if needed.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Tell your doctor about any doses you miss.

Storage—

Keep out of the reach of children.

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Do not keep outdated medicine or medicine no longer needed.

Precautions While Using This Medicine:

Tell all medical doctors and dentists you go to that you are taking this medicine.

Always check with your health care professional before you start or stop taking any other medicine. This includes any nonprescription (over-the-counter [OTC]) medicine, even aspirin. Other medicines may change the way this medicine affects your body

Your doctor should check your progress at regular visits. A blood test must be taken regularly to see how fast your blood is clotting. This will help your doctor decide how much medicine you need.

Side Effects of This Medicine:

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

Less common
(With menadiol or high doses of phytonadione in newborns)
Decreased appetite
decreased movement or activity
difficulty in breathing
enlarged liver
general body swelling
irritability
muscle stiffness
paleness
yellow eyes or skin
Rare
(With injection only)
Difficulty in swallowing
fast or irregular breathing
lightheadedness or fainting
shortness of breath
skin rash, hives and/or itching
swelling of eyelids, face, or lips
tightness in chest
troubled breathing and/or wheezing
Rare
Blue color or flushing or redness of skin
dizziness
fast and/or weak heartbeat
increased sweating
low blood pressure (temporary)

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common
Flushing of face
redness, pain, or swelling at place of injection
skin lesions at place of injection (rare)
unusual taste

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.


Last Updated: 4/4/2014

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