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PubMed1993

Reversal of excessive effect of regular anticoagulation: low oral dose of phytonadione (vitamin K1) compared with warfarin discontinuation.

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. INR was determined after 24 h (day 1), after which both groups continued with their usual dose of warfarin. After 48 h (day 2), warfarin dosage was changed according to the INR value. On day 9, INR values were determined again. Five out of twelve patients in group A had INR values > 5 on day 1. One patient in group A had an INR value < 5 both on days 1 and 2. All eleven patients in group B had INR values < 5 on day 1, and all but one on day 2. On day 9, INR values were acceptable (INR 2.0-4.5) in ten group A patients and eight group B patients. These findings suggest that a low oral dose of vitamin K1 is a convenient treatment for excessive anticoagulation in patients with no bleeding complications.

Adult↗

PubMed1998

Evaluation of excessive anticoagulation in a group model health maintenance organization.

BACKGROUND: The fourth American College of Chest Physicians Consensus Conference on Antithrombotic Therapy recently published guidelines that included recommendations regarding the management of excessive anticoagulation. Limited data are available to support these recommendations. OBJECTIVES: To assess management and outcomes of excessive anticoagulation in a group model health maintenance organization, compare management with the published guidelines, and analyze the cost of treatment strategies. METHODS: A search of computerized laboratory information identified patients with an international normalized ratio (INR) of greater than 6.0 during the 9-month study. Pertinent data were collected through a retrospective medical record review. Information was concurrently collected for cost analyses. RESULTS: The analysis included 301 episodes of excessive anticoagulation among 248 patients. Most (83%) episodes of elevated INRs were managed conservatively by a temporary discontinuation of warfarin sodium therapy until the INR was in a therapeutic range. Conservative management resulted in no sequelae in 212 (85.1%) of 249 episodes. Two episodes (0.8%) of major bleeding evolved in patients managed conservatively. No sequelae were documented in 23 (44%) of 52 episodes of phytonadione (vitamin K1) administration. Sixteen (31%) episodes of major bleeding were documented, but bleeding occurred before phytonadione administration in all cases. Administering phytonadione resulted in hospital admission for 3 patients--2 (3.8%) because of thromboembolism and 1 (1.9%) for the administration of heparin sodium. Cost-effectiveness analysis determined that treatment with phytonadione is 7 times more costly than conservative management when INRs are between 6.0 and 10.0. CONCLUSIONS: Most episodes of excessive anticoagulation were not managed per consensus guidelines. The higher the INR, the more likely were interventions to adhere to the guidelines. Administering phytonadione to patients with a moderate elevation of INRs (6.0-10.0) may be unnecessary. Based on this study, conservative management is a viable option.

Aged↗

PubMed2002

A survey of oral vitamin K use by anticoagulation clinics.

BACKGROUND: Despite published reports of its safety and efficacy, oral vitamin K (phytonadione) may not be widely used for patients with warfarin-associated coagulopathy. We tested the hypothesis that recommendations for phytonadione use from the American College of Chest Physicians (ACCP) Fifth Consensus Conference on Antithrombotic Therapy are not routinely incorporated into the clinical practice of many anticoagulation clinics. METHODS: Surveys were mailed to 100 separate clinics in the southwestern region of the United States that are members of the Anticoagulation Forum, an association of anticoagulation clinic personnel and medical directors in the United States and Canada. Respondents were presented with 4 scenarios involving asymptomatic patients taking warfarin whose international normalized ratio is supratherapeutic. In each scenario, the respondents were told the patient's international normalized ratio and whether the patient was at "high" risk for bleeding. RESULTS: Of 53 respondents, 13 (25%) indicated that their clinics never use oral phytonadione. Eighteen (34%) indicated that their clinics use subcutaneous phytonadione, despite the absence of a recommendation for this in the ACCP guidelines published in 1998. For each scenario, we made a judgment as to whether the respondent's management was consistent with guidelines found in the ACCP Fifth Consensus Conference on Antithrombotic Therapy. Overall, only 17 respondents (32%) provided all 4 answers consistent with the ACCP recommendations. CONCLUSION: For patients with supratherapeutic international normalized ratio values, our survey suggests that a substantial number of anticoagulation clinics underutilize oral phytonadione.

Administration, Oral↗

PubMed2006

Vitamin K and the prevention of fractures: systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Observational and some experimental data suggest that low intake of vitamin K may be associated with an increased risk of fracture. OBJECTIVE: To assess whether oral vitamin K (phytonadione and menaquinone) supplementation can reduce bone loss and prevent fractures. DATA SOURCES: The search included the following electronic databases: MEDLINE (1966 to June 2005), EMBASE (1980 to June 2005), the Cochrane Library (issue 2, 2005), the ISI Web of Science (1945 to June 2005), the National Research Register (inception to the present), Current Controlled Trials, and the Medical Research Council Research Register. STUDY SELECTION: Randomized controlled trials that gave adult participants oral phytonadione and menaquinone supplements for longer than 6 months were included in this review. DATA EXTRACTION: Four authors extracted data on changes in bone density and type of fracture. All articles were double screened and double data extracted. DATA SYNTHESIS: Thirteen trials were identified with data on bone loss, and 7 reported fracture data. All studies but 1 showed an advantage of phytonadione and menaquinone in reducing bone loss. All 7 trials that reported fracture effects were Japanese and used menaquinone. Pooling the 7 trials with fracture data in a meta-analysis, we found an odds ratio (OR) favoring menaquinone of 0.40 (95% confidence interval [CI], 0.25-0.65) for vertebral fractures, an OR of 0.23 (95% CI, 0.12-0.47) for hip fractures, and an OR of 0.19 (95% CI, 0.11-0.35) for all nonvertebral fractures. CONCLUSIONS: This systematic review suggests that supplementation with phytonadione and menaquinone-4 reduces bone loss. In the case of the latter, there is a strong effect on incident fractures among Japanese patients.

Bone Density↗

PubMed2003

A retrospective evaluation of the management of excessive anticoagulation in an established clinical pharmacy anticoagulation service compared to traditional care.

BACKGROUND: Analysis of the outcomes associated with episodes of excessive anticoagulation (international normalized ratio [INR] > 6.0) managed by physicians in a group model health maintenance organization (HMO) revealed opportunities for improvement. A centralized, telephone follow-up Clinical Pharmacy Anticoagulation Service (CPAS) was later implemented in the same HMO. We sought to compare the outcomes of excessive anticoagulation episodes managed by CPAS pharmacists to traditional physician management. METHODS: Computerized laboratory information was used to identify episodes of excessive anticoagulation managed by CPAS clinical pharmacists during the 6-month study. Pertinent data were collected through retrospective medical record review. Results were compared to a similar analysis conducted prior to CPAS implementation (traditional management). RESULTS: A total of 313 INR episodes >6.0 were identified in the CPAS group compared to 301 in the traditional management group. 6.3% of patients in the traditional management group experienced major bleeding compared to 1.3% in the CPAS group (p = 0.001). The majority of excessive anticoagulation episodes in both groups were managed by temporarily withholding warfarin therapy. Phytonadione was administered more frequently in the traditional management group than the CPAS group, 17.0% vs. 6.4%, respectively (p < 0.001). Traditional management patients also received higher doses of phytonadione than CPAS patients, 13.0 mg vs. 3.3 mg, respectively (p < 0.001). Aggressive use of phytonadione in the traditional management group resulted in two episodes of iatrogenic thromboembolism while no such episodes occurred in the CPAS group. CONCLUSIONS: The management of excessive anticoagulation by a centralized telephone follow-up anticoagulation service staffed by clinical pharmacists resulted in improved clinical outcomes compared to traditional management.

Aged↗

PubMed1987

Hypoprothrombinemia associated with cefoperazone therapy.

Cefoperazone, a beta-lactam antibiotic with a methylthiotetrazole side chain, has been reported infrequently to cause hypoprothrombinemia and hemorrhage. We retrospectively analyzed the records of 80 patients who had been given this drug for more than 72 hours. Nine patients received vitamin K1 (phytonadione) prophylaxis and had no evidence of hemorrhage. Of the remaining 71 patients, 32 had prothrombin times measured; 14 of them had hypoprothrombinemia. Prothrombin times ranged from 14.8 to 97.3 seconds at a mean of 6.2 days after initiation of therapy. Seven of the 14 patients had clinically significant hemorrhage and five required transfusions. Two patients with clinically evident hemorrhage died during or immediately after cefoperazone therapy. Prothrombin times rapidly returned to normal in all patients treated with phytonadione. We believe hypoprothrombinemia is a more common complication of cefoperazone therapy than is generally acknowledged, and is preventable. Unless clinically contraindicated, we recommend that all patients treated with cefoperazone receive phytonadione prophylaxis.

Aged↗

PubMed2000

Prospective study of the outcomes of ambulatory patients with excessive warfarin anticoagulation.

BACKGROUND: Warfarin sodium therapy is highly effective in preventing thromboembolism. Its major toxic effect is hemorrhage, the risk of which increases with the international normalized ratio (INR). Data on the rate of major hemorrhage and the rate of INR decay after an episode of excessive anticoagulation therapy would help guide management of elevated INRs in the outpatient setting. METHODS: We prospectively followed up outpatients in an anticoagulant therapy unit from April 24, 1995, through March 1, 1996. Study patients had to be taking warfarin for longer than 1 month and have an INR target range of 2.0 to 3.0. Consecutive outpatients with an INR greater than 6.0 were identified and compared with a randomly selected concurrent set of patients whose INR was in the target range. Major hemorrhage was defined as fatal, intracranial, or requiring hospitalization and transfusion of at least 2 U of blood. RESULTS: One hundred fourteen patients with INRs greater than 6.0 were identified and compared with 268 patients with INRs in the target range. None of the patients had clinically apparent bleeding at the time of the INR measurement, and none received phytonadione (vitamin K1). Patients did not differ significantly in age, sex, indication, or duration of warfarin therapy. Ten patients with an INR greater than 6.0 (8.8%; 95% confidence interval, 4.3%-15.5%) sought medical attention for abnormal bleeding, and 5 of these experienced a major hemorrhage during 14-day follow-up (4.4%; 95% confidence interval, 1.4%-9.9%) compared with none of the patients with an in-range INR (P<.001). Thirty-three percent of patients with INRs greater than 6.0 had INRs less than 4.0 within 24 hours, 55% within 48 hours, 73% within 72 hours, and nearly 90% within 96 hours of temporary discontinuation of warfarin therapy. CONCLUSIONS: Outpatients with INRs greater than 6.0 face a significant short-term risk of major hemorrhage. Randomized trials are needed to determine the net benefit of preventive treatment with phytonadione.

Adult↗

PubMed1984

Potential for endotoxin-activated Kupffer's cells to induce microvascular thrombosis.

The potential contribution of Kupffer's cells, le, hepatic macrophages (HM phi s) to the diffuse microvascular thrombosis seen during septicemia was evaluated by measuring the ability of a homogeneous population of explanted HM psi s to express procoagulant activity (PCA). Addition of as little as 100 ng/mL of endotoxin stimulated a 30-fold increase over control values of PCA within eight hours. This PCA was membrane associated and functioned externally to the macrophage. Sensitivity to heat (56 degrees C) and diisopropyl fluorophosphate differentiated this PCA from typical tissue thromboplastin activity. The increase in PCA was blocked by pretreatment with warfarin sodium (a phytonadione blocker) and could be restored by addition of phytonadione. These studies showed that endotoxin induces in HM psi s a significant increase in PCA, functioning like coagulation factor VII. These results support a role for Kupffer's cells in the initiation of microvascular thrombosis in endotoxemia.

Animals↗

PubMed1992

Fatal rodenticide poisoning with brodifacoum.

The increased prevalence of rodents resistant to warfarin led to the development of the hydroxycoumarin anticoagulant brodifacoum. A 25-year-old man attempted suicide by consuming four boxes of d-CON Mouse-Prufe II; each box contains 42 g of bait that is 0.005% brodifacoum. He presented to a hospital nine days later with syncope, hematochezia, gross hematuria, epistaxis, anemia, and a severe coagulopathy. Radiographic studies were consistent with pleural, pericardial, and mediastinal hemorrhages. Vitamin K and fresh frozen plasma were given, and he was later discharged on oral phytonadione (vitamin K1). The patient's coagulopathy recurred, necessitating multiple plasma transfusions and prolonged treatment with oral phytonadione. Fifteen weeks after hospital discharge, he presented again with a history of additional brodifacoum ingestion. Neurologic status was initially normal, but in the emergency department he suddenly became comatose soon after emesis was induced with syrup of ipecac. Computed tomography of the brain revealed a subarachnoid hemorrhage that led to brain death less than 24 hours later. This case demonstrates the severe and prolonged coagulopathy that can result from ingestion of brodifacoum, a compound that has a toxic potency about 200-fold that of warfarin and a half-life as much as 60 times longer.

4-Hydroxycoumarins↗

PubMedDate not supplied

Intraspinal hematoma as a complication of anticoagulant therapy.

Two patients who developed intraspinal hematomas associated with anticoagulation therapy are described, and the pathology, clinical presentation, risks, evaluation and management of this rare hemorrhagic consequence, which results in spinal cord injury (SCI), are discussed. A 49-year-old man was taking warfarin sodium 7.5 mg orally every day for two weeks for thrombophlebitis. Prothrombin time (PT) was 24 sec (control = 17 sec). Two days after a dosage reduction for a PT of 36.5 sec (control = 11 sec), he developed severe neck pain, numbness and weakness of the legs, and then quadriplegia. Warfarin therapy was discontinued, and 25 mg of phytonadione was administered intravenously. An epidural hematoma was removed via a C3-C6 laminectomy, and the patient remains a C3 complete quadriplegic. The second patient was a 64-year-old man who was taking warfarin sodium 5 mg and 7.5 mg orally on alternate days following an aortic-valve replacement. PT was maintained at 1.5 times the control value. Four years later, he fell and sustained flexion distraction and compression injuries of the spine at the L1-L2 level. He complained of severe neck pain and headache. Warfarin therapy was stopped, and 10 mg of phytonadione was administered i.v. During a hospital transfer he developed complete paraplegia. PT was 12.4 sec (control = 10.8 sec). Twelve days later, a laminectomy was performed to remove the T6-L1 subdural hematoma revealed by computed tomography (CT). The patient remains a T5 complete paraplegic. Unlike intracranial hemorrhage, intraspinal hemorrhage usually occurs in the epidural space, most often in the dorsal thoracic spine.(ABSTRACT TRUNCATED AT 250 WORDS)

Anticoagulants↗

PubMed1993

Case management and plasma half-life in a case of brodifacoum poisoning.

Brodifacoum is a readily available, second-generation anticoagulant rodenticide (superwarfarin) that causes extended depletion of vitamin K1-dependent clotting factors. Brodifacoum ingestions are being reported with increasing frequency. For the first time, we compare plasma brodifacoum concentration to prothrombin levels over time in a case of brodifacoum poisoning. Brodifacoum was eliminated according to a two-compartment model, with an initial half-life of 0.75 days and a terminal half-life of 24.2 days. On admission, the brodifacoum level was 731 micrograms/L and the patient suffered severe urinary tract hemorrhage, requiring transfusion of blood products. Persistently increased prothrombin times necessitated treatment with phytonadione up to 80 mg/d for 4 months, until the brodifacoum level reached 10 micrograms/L. These data may help project the duration of phytonadione treatment required in future cases of brodifacoum poisoning. Superwarfarin exposure must be suspected in an otherwise unexplained vitamin K1-deficient coagulopathy.

4-Hydroxycoumarins↗

PubMed1998

Snake oil for the 21st century.

Dermatology has been associated with quackery for at least a century. The dictionary defines a quack as "a pretender to medical knowledge or skill; ignorantly or falsely pretending to cure." The term quack is derived from quacksalver, or one who quacks like a duck in promoting his salves. Quacksalvers hacked many potions, including snake oil, with claims that it cured everything from dermatitis to rheumatism. With the current promulgation of skin "products" and their promotion and even sale by dermatologists, and the use of treatments of no proven efficacy, this association between dermatology and quackery is set to continue well into the 21st century. The list of offending treatments includes silicone gel sheets and onion extract cream (Mederma) for keloids, alpha-hydroxy acid creams and peels, topical ascorbic acid and phytonadione, "laser resurfacing," and cimetidine for warts, to name only a few.

Clinical Trials as Topic↗

PubMed2003

The incidence of recurrent venous thromboembolism after treatment with vitamin K antagonists in relation to time since first event: a meta-analysis.

BACKGROUND: After a first episode of venous thromboembolism, patients are treated with vitamin K (phytonadione) antagonists. There are indications that the risk of recurrence after treatment with vitamin K antagonists decreases relative to the time since the first event. The aim of the present meta-analysis is to describe the risk of recurrent venous thromboembolism after treatment with vitamin K antagonist in relation to the time since the index event. METHODS: Computerized searches in MEDLINE and EMBASE databases; reference checks of pertinent articles; personal communication with colleagues to find randomized clinical trials and cohort studies in which patients with venous thromboembolism were treated with vitamin K antagonists. Per treatment arm, 2 reviewers independently extracted data on the number of recurrent events and the duration of follow-up per time period of 3 months. RESULTS: A total of 135 potentially eligible studies were identified. Of these, 18 studies could be included, comprising 25 treatment arms that could be analyzed. Treatment arms were divided into 3 groups based on treatment duration (short, medium, and long). For all 3 groups, the monthly incidence immediately after discontinuation of treatment was high and declined rapidly thereafter. The monthly incidence after 9 months seemed independent of the treatment duration. CONCLUSIONS: There is a diminishing risk of recurrent venous thromboembolism over time and a stabilization after 9 months independent of the duration of the initial treatment with vitamin K antagonists. These findings have important implications for decision making about the optimal duration of treatment with vitamin K antagonists.

Anticoagulants↗

PubMed2003

Are there teratogenic risks associated with antidotes used in the acute management of poisoned pregnant women?

OBJECTIVE: We reviewed evidence suggesting teratogenic risk associated with the use of antidotes in the acute management of poisoned pregnant women. METHODS: Medline, Toxline, and DART/ETIC searches; references of retrieved articles, pertinent databases and textbooks were also searched. RESULTS: There are case reports or case series of women who received antidotes for poisoning during (*) or after (+) the period of organogenesis who showed no fetal adverse effects. Some antidotes, however, have no teratogenic risk: atropine (cohort/surveillance studies)+, calcium (oral supplement: cohort study)+ and pyridoxine (Bendectin studies). Also, ethanol+, methylene blue (intra-amniotic injection but not oral) and penicillamine* can be considered teratogens but their risks in the treatment of poisonings are unknown. There is no epidemiologic study evaluating the risk of the following antidotes during pregnancy: N-acetylcysteine(*+), BAL (dimercaprol)+, black widow spider antivenin+, calcium EDTA+, crotalidae antivenin, crotalidae polyvalent immune FAB, cyanide antidote kit (amyl and sodium nitrate, sodium thiosulfate), deferoxamine(*+), digoxin immune FAB+, DMSA+, flumazenil+, fomepizole, methylene blue (IV), naloxone, physostigmine, pralidoxime+, protamine+; and parenteral pharmacologic doses of calcium+, folinic acid*, glucagon+, hydroxycobalamin, phytonadione (vitamin K), and pyridoxine. CONCLUSIONS: Despite the limited evidence supporting the risk of antidote use during pregnancy, antidotes should be used when there is a clear maternal indication to decrease the morbidity or mortality associated with poisoning. The only exception may be penicillamine, which is a teratogen. Better antidotes exist for most poisonings that penicillamine could potentially treat. At this time, there is no known fetal indication for all antidotes. Reporting the use of an antidote during pregnancy should be encouraged, especially if used during the critical period of organogenesis.

Abnormalities, Drug-Induced↗

PubMed2000

Management and dosing of warfarin therapy.

When initiating warfarin therapy, clinicians should avoid loading doses that can raise the International Normalized Ratio (INR) excessively; instead, warfarin should be initiated with a 5-mg dose (or 2 to 4 mg in the very elderly). With a 5-mg initial dose, the INR will not rise appreciably in the first 24 hours, except in rare patients who will ultimately require a very small daily dose (0.5 to 2.0 mg). Adjusting a steady-state warfarin dose depends on the measured INR values and clinical factors: the dose does not need to be adjusted for a single INR that is slightly out of range, and most changes should alter the total weekly dose by 5% to 20%. The INR should be monitored frequently (eg, 2 to 4 times per week) immediately after initiation of warfarin; subsequently, the interval between INR tests can be lengthened gradually (up to a maximum of 4 to 6 weeks) in patients with stable INR values. Patients who have an elevated INR will need more frequent testing and may also require vitamin K1. For example, a nonbleeding patient with an INR of 9 can be given low-dose vitamin K1 (eg, 2.5 mg phytonadione, by mouth). Patients who have an excessive INR with clinically important bleeding require clotting factors (eg, fresh-frozen plasma) as well as vitamin K1.

Administration, Oral↗

PubMed1989

Nutritional deficiency and the skin.

Cutaneous changes occur in deficiency states of many nutritional elements: ascorbic acid, retinol, protein-energy, cyanocobalamin, phytonadione (vitamin K), biotin, ribroflavin, pyridoxine, niacin, essential fatty acids, and zinc. There are also inherited disorders of copper, biotin, zinc, and tryptophan metabolism. Cutaneous vitamin D synthesis is inhibited by sunscreen use. The striking skin changes of the glucagonoma syndrome may be related to nutritional pathways.

Deficiency Diseases↗

PubMed1998

Vitamin K1-induced localized scleroderma (morphea) with linear deposition of IgA in the basement membrane zone.

We describe a 45-year-old white man in whom distinctive clinical and histologic features of localized scleroderma developed at sites of injection of vitamin K1 (phytonadione). A direct immunofluorescence test demonstrated prominent linear deposition of IgA along the basement membrane zone. No circulating antibasement membrane zone IgA antibodies were identified on indirect immunofluorescence testing. We believe that the unusual immunofluorescence finding in our patient is nonspecific and represents an epiphenomenon caused by cutaneous injury.

Antifibrinolytic Agents↗

PubMed1997

Vitamin K2 and its derivatives induce apoptosis in leukemia cells and enhance the effect of all-trans retinoic acid.

Geranylgeraniol, a polyprenylalcohol composing the side chain of vitamin K2 (VK2), was previously reported to be a potent inducer of apoptosis in tumor cell lines (Ohzumi H et al, J Biochem 1995; 117: 11-13). We examined the apoptosis-inducing ability of VK2 (menaquinone 3 (MK3), MK4 and MK5) and its derivatives such as phytonadione (VK1), as well as polyprenylalcohols with side chains of various lengths including farnesol (C15-OH; FO), geranylgeraniol (C20-OH; GGO), and geranylfarnesol (C25-OH; GFO) toward leukemia cells in vitro. MK3, MK4, MK5 and GFO (at 10 microM) showed a potent apoptosis-inducing activity for all freshly isolated leukemia cells tested and for leukemia cell lines such as NB4, an acute promyelocytic leukemia (APL)-derived cell line and MDS92, a cell line derived from a patient with myelodysplastic syndrome, although there were some differences depending on the cells tested. In contrast, VK1 showed no effect on any of the leukemia cells. The combination of MK5 plus all-trans retinoic acid (ATRA) resulted in enhanced induction of apoptosis in both freshly isolated APL cells and NB4 cells as compared to each reagent alone. These data suggest the possibility of using VK2 and its derivatives for the treatment of myelogenous leukemias, including APL.

Apoptosis↗