Mephyton Side Effects
Generic Name: phytonadione
Note: This document contains side effect information about phytonadione. Some of the dosage forms listed on this page may not apply to the brand name Mephyton.
Some side effects of Mephyton may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to phytonadione: oral tablets, parenteral injection
Side effects include:
Parenteral Administration: Pain, swelling, and tenderness at the injection site, transient “flushing sensations,“ “peculiar” sensations of taste.
Fatal anaphylactic reaction reported after IV and IM administration. (See Boxed Warning.)
For Healthcare Professionals
Applies to phytonadione: compounding powder, injectable solution, oral tablet
Severe localized cutaneous reactions have been described in several case reports following multiple intramuscular, and subcutaneous, injections of phytonadione (the active ingredient contained in Mephyton) Erythematous and sometimes indurated and itchy plaques have developed at the various sites of injection within a few days to several weeks after initiation of treatment, often spreading from the buttocks to the sacrum and down the thighs, creating a "gunbelt and holster" pattern. Transient widespread maculopapular erythematous eruptions have also been reported. The rashes have generally resolved within 2 to 12 weeks and have left no residual scarring. In some cases, scleroderma-like lesions have developed at the injection sites over a period of 2 years and persisted for much longer durations than the original plaques. Sclerodermoid lesions have also been observed without prior formation of the erythematous plaques, but they have been invariably characterized by a greater delay of onset (up to 2 years after phytonadione treatment). In addition, intermittent exacerbations of the lesions and pruritus after initial resolution has been reported, suggesting the reaction may be prolonged.
Underlying factors common to many of the cases reported in Europe and North America include the presence of liver disease and the cumulative administration of large doses of phytonadione. One group of investigators suggested that concomitant liver disease may be of importance insofar as it indirectly contributed to the large doses. The investigators felt the cumulative dose to be of some significance, since most cases had greater than 100 mg before the reaction occurred and the cases that progressed to the pseudoscleroderma stage received doses individually totaling more than 500 mg. However, smaller doses have reportedly triggered similar responses in some patients, so it is unlikely that the reaction is entirely dose-related, if at all. In any case, the reaction is apparently unrelated to the nature or severity of the liver disease. One report from Japan found no correlation altogether, as most of its cases occurred in the absence of any liver dysfunction.
Intradermal and skin patch testing have led many researchers to suspect a local allergic reaction to the phytonadione itself or some additive in the preparation (e.g. phenol, polyethoxylated castor oil), although doubts have been expressed as to whether an immunologic mechanism is even involved, based on inconsistent results from histologic studies done in a few of the cases.
Local side effects have included pain, swelling, and tenderness at the injection site. Side effects have rarely included erythematous, tender, and indurated plaques following multiple intramuscular or subcutaneous injections.
Cardiovascular effects have rarely included rapid and weak pulse and brief hypotension. Shock and cardiac arrest have rarely occurred during or following parenteral administration.
Fatalities and other severe reactions have occurred during or immediately after the parenteral administration of phytonadione (the active ingredient contained in Mephyton) The majority of these reactions have occurred with intravenous administration. These reactions resemble hypersensitivity or anaphylaxis and include shock and cardiac or respiratory arrest. Feelings of uneasiness, flushing, diaphoresis, chest pain, tachycardia, cyanosis, weakness, and dyspnea may precede the cardiopulmonary event. These severe reactions are more likely with, but are not limited to, rapid infusions of undiluted drug.
Hypersensitivity side effects have rarely included serious anaphylactoid reactions and death.
Gastrointestinal side effects have rarely included 'peculiar' sensations of taste.
Respiratory side effects have rarely included dyspnea and cyanosis. Respiratory arrest has rarely occurred during or following parenteral administration.
Other side effects have rarely included dizziness and profuse sweating.
Hyperbilirubinemia has occurred rarely in newborns, and is usually seen following parenteral administration of doses which exceed the recommend dose.
Other side effects have included hemolysis, jaundice, and hyperbilirubinemia in newborns, especially premature infants.
Dermatologic side effects including a case of Nicolau syndrome have been reported.
More about Mephyton (phytonadione)
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