GENERIC NAME: vitamin K-1, phytonadione
BRAND NAME: Mephyton
DISCONTINUED BRAND: AquaMephyton in the US
DRUG CLASS AND MECHANISM: Phytonadione is a synthetic form of vitamin K that is chemically identically to the naturally occurring vitamin K. Vitamin K is found in many foods from both plant and animal sources. Common sources of vitamin K include green leafy vegetables such as
- Brussels sprouts,
- collard greens,
- lettuce, and
Vitamin K plays a crucial role in blood coagulation and the formation of blood clots. Vitamin K is necessary for the production of clotting factors in the liver including active prothrombin (factory II), proconvertin (factor VII), plasma thromboplastin component (factor IX), and Stuart factor (factor X). The FDA approved phytonadione 1940.
PRESCRIBED FOR: Vitamin K is used to prevent and treat hypoprothrombinemia (deficiency of factor II or prothrombin) and bleeding caused by warfarin (Coumadin), a commonly used blood thinner. It is also used to treat and prevent drug induced vitamin K deficiency caused by other medications. Additionally, it is used to prevent and treat bleeding disorders in newborns and to replace low levels of vitamin K caused by malabsorption or inability to synthesize vitamin K.
SIDE EFFECTS: Serious hypersensitivity reactions, including anaphylactoid reactions and death have been reported with use of injectable phytonadione. The majority of these cases were associated with use of intravenous phytonadione.
Other side effects reported with use of injectable phytonadione include:
- injection site pain or discomfort,
- taste disturbances,
- rapid or weak pulse,
- profuse sweating,
- low blood pressure (hypotension),
- shortness of breath, and
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Need help identifying pills and medications?
Use the pill identifier tool on RxList.