Mephyton (Phytonadione) - Summary

MEPHYTON SUMMARY

MEPHYTON^®
(PHYTONADIONE)
TABLETS
Vitamin K₁

MEPHYTON tablets possess the same type and degree of activity as does naturally-occurring vitamin K, which is necessary for the production via the liver of active prothrombin (factor II), proconvertin (factor VII), plasma thromboplastin component (factor IX), and Stuart factor (factor X).

MEPHYTON is indicated in the following coagulation disorders which are due to faulty formation of factors II, VII, IX and X when caused by vitamin K deficiency or interference with vitamin K activity.

MEPHYTON tablets are indicated in:

• anticoagulant-induced prothrombin deficiency caused by coumarin or indanedione derivatives;
• hypoprothrombinemia secondary to antibacterial therapy;
• hypoprothrombinemia secondary to administration of salicylates;
• hypoprothrombinemia secondary to obstructive jaundice or biliary fistulas but only if bile salts are administered concurrently, since otherwise the oral vitamin K will not be absorbed.

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NEWS HIGHLIGHTS

Published Studies Related to Mephyton (Phytonadione)

Comparison of oral vs intravenous phytonadione (vitamin K1) in patients with excessive anticoagulation: a prospective randomized controlled study. [2003.11.10]
BACKGROUND: Treatment of patients with excessive anticoagulation is routinely done by intravenous phytonadione (vitamin K1). Oral administration of phytonadione has been shown to be an effective alternative to the intravenous route, but these methods have never been compared directly. Our objective was to compare efficacy and safety of intravenous vs oral phytonadione treatment in patients with excessive anticoagulation without bleeding... CONCLUSION: Oral administration of phytonadione had similar efficacy and safety as intravenously administered phytonadione and may be suitable for treatment of patients with excessive anticoagulation.

Randomized, placebo-controlled trial of oral phytonadione for excessive anticoagulation. [2000.10]
STUDY OBJECTIVE: To compare the efficacy of managing excessive anticoagulation in the absence of bleeding by either omitting warfarin therapy alone or administering oral phytonadione in addition to omitting warfarin therapy... CONCLUSION: The addition of oral phytonadione 2.5 mg reduced the time to achieve an INR of 4.0 by approximately 1 day compared with omitting warfarin therapy alone. Adverse events did not differ between the two groups. Both strategies were effective in managing asymptomatic patients with INRs of 6.0-10.0. Oral phytonadione may be most appropriate for patients at high risk for bleeding in whom the benefit of prompt INR reduction would outweigh the thromboembolic risk associated with INR overcorrection.

Time course of reversal of anticoagulant effect of warfarin by intravenous and subcutaneous phytonadione. [1999.12.13]
BACKGROUND: Excessive anticoagulation increases the risk of hemorrhagic complications associated with oral anticoagulant therapy. Oral or parenteral phytonadione is used to reverse excessive anticoagulation. Intravenous (IV) phytonadione, while effective, is associated with a small risk of serious anaphylactic reactions. Subcutaneous (SC) administration is safer, but there is little information on its relative efficacy in small doses... CONCLUSIONS: For patients who are excessively anticoagulated with warfarin, small doses of SC phytonadione may not correct the INR as rapidly or as effectively as when administered IV. Higher doses must be considered for more rapid and complete reversal of anticoagulation by the SC route.

Reversal of excessive effect of regular anticoagulation: low oral dose of phytonadione (vitamin K1) compared with warfarin discontinuation. [1993.10]
To determine the best way to reverse the excessive effect of regular anticoagulation in patients with INR > 5 and no bleeding complications, 23 patients with INR > 5 were randomly subdivided into two groups: group A (n = 12) discontinued warfarin for one day and group B (n = 11) received 2 mg of vitamin K1 orally in addition to the usual warfarin dose...

Treatment of excessive anticoagulation with phytonadione (vitamin K): a meta-analysis. [2006.02.27]
BACKGROUND: Patients taking oral anticoagulants with an international normalized ratio (INR) greater than 4.0 are at increased risk for bleeding. We performed a meta-analysis to determine the effectiveness of phytonadione (vitamin K) in treating excessive anticoagulation... CONCLUSIONS: Limited evidence suggests that oral and intravenous vitamin K are equivalent and more effective for excessive anticoagulation than simply withholding warfarin sodium. Subcutaneous vitamin K, however, is inferior to oral and intravenous vitamin K for this indication and is similar to placebo. Whether treatment with vitamin K decreases hemorrhagic events cannot be determined from the published literature.

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Clinical Trials Related to Mephyton (Phytonadione)

Use of Phytonadione to Reduce International Normalized Ratio (INR) Variability in Patients on Long-term Warfarin Therapy [Recruiting]
Background: Warfarin is used as an anti-coagulant in patients at risk of developing thrombosis. It has a narrow therapeutic index necessitating close monitoring of International Normalized Ratio (INR). According to a meta-analysis, patients were in therapeutic range only 63. 6% of the time. This increases the risk of bleeding or thrombosis. Various retrospective and prospective studies have looked at supplementation with phytonadione in these patients to reduce the variability of INR showing an improvement in variability. Most of these studies have only been done in a small number of patients already on warfarin therapy. This study will focus on patients newly starting warfarin therapy. Methods: This study is a prospective, randomized, controlled trial performed at James A. Haley Veterans' Hospital (JAHVA). Patients who meet criteria and sign informed consent will receive either phytonadione with warfarin or warfarin alone. Based on a power calculation for 80%, a total of 370 patients will be enrolled (185 participants in each arm). Participants will be randomized to either intervention or control. Intervention group participants will be prescribed their usual starting dose of warfarin along with 200 mcg phytonadione by mouth daily. Control group participants will be prescribed their usual starting dose of warfarin. Both groups will follow the usual standard of care. They will come in for a follow-up INR and warfarin dose titration at least once per week until therapeutic, and then as instructed up to every 6 weeks thereafter. Both groups will participate in anticoagulation clinic activities that constitute the current standard of care. Intervention will last for a total of 6 months for each participant once enrolled. Hypothesis: Participants in the intervention group being supplemented with 200mcg of phytonadione will spend more total time with a therapeutic INR than participants in the control group.

Vitamin K1 to Slow Progression of Vascular Calcification in HD Patients [Recruiting]
Patients on hemodialysis (HD) exhibit an immensely increased cardiovascular mortality associated with extensive vascular calcification (VC). In the past years the development of VC was discovered to be actively regulated and as being influenced by inhibitors of calcification (e. g. matrix-Gla-protein, fetuin-A). MGP is produced by vascular smooth muscle cells and needs post-translational modification by vitamin K dependent gamma-carboxylation to be fully active. Based on the demonstration of increased PIVKA-II levels, about 97% of all HD patients exhibit insufficient carboxylation activity. We therefore aim in this randomized, controlled study to retard the progress of coronary and aortal calcification as assessed by thoracic multislice-CT by the thrice weekly administration of 5 mg vitamin K1 (phylloquinone) to a total of 348 HD patients over a period of 18 months.

Biocomparison Study [Completed]
The effects of two vitamin K-forms on carboxylation of the vitamin K-dependent proteins osteocalcin and matrix-gla protein will be compared after supplementing these vitamins in a nutritional dose range. The investigators hypothesized that MK-7 is more effective than K1 at a dose comparable to the RDA of vitamin K.

Low Dose Supplementation to Improve Anticoagulation Control With Oral Vitamin K as an Adjuvant to Warfarin Therapy [Completed]
The main objective of this study is to assess the effectiveness of low dose Vitamin K1 (200 micrograms per day) at improving anticoagulation control in unstable patients on warfarin. This study will also aim to look at effectiveness in the context of genes known to influence warfarin metabolism, variability in the consumption of Vitamin K rich foods, and patient

knowledge about warfarin anticoagulation - - factors which have been associated with

anticoagulation control and which can influence the effectiveness of this intervention in clinical practice.

Vitamin K Supplementation in Patients on Hemodialysis [Recruiting]
The purpose of this study is to determine whether vitamin K supplementation will improve anticoagulation control in patients on hemodialysis taking warfarin for atrial fibrillation. Patients who participate will receive vitamin K1 three times a week on dialysis days for a period of four months. INR levels collected during this period will be compared to the four month period prior to receiving the vitamin K1 to determine if vitamin K improves the standard deviation of INRs and time in therapeutic range.

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