Jornal Vascular Brasileiro
https://jvascbras.org/article/doi/10.1590/jvb.2014.004
Jornal Vascular Brasileiro
Original Article

Comparison of initial loading doses of 5 mg and 10 mg for warfarin therapy

Comparação da dose inicial de 5 mg ou 10 mg para o início da terapia com varfarina

Sidnei Lastória; Arcangelo T. Fortes Jr; Francisco H. Abreu Maffei; Marcone Lima Sobreira; Hamilton A. Rollo; Regina Moura; Winston Bonetti Yoshida

http://dx.doi.org/10.1590/jvb.2014.004 J Vasc Bras, vol.13, n1, p.12-17, 2014
PDF English
PDF Português
SciELO
Downloads: 0
Views: 865

Abstract

CONTEXT: The question of what is the best loading dosage of warfarin when starting anticoagulant treatment has been under discussion for ten years. We were unable to find any comparative studies of these characteristics conducted here in Brazil.OBJECTIVE: To compare the safety and efficacy of two initial warfarin dosage regimens for anticoagulant treatment.METHODS: One-hundred and ten consecutive patients of both sexes, with indications for anticoagulation because of venous or arterial thromboembolism, were analyzed prospectively. During the first 3 days of treatment, these patients were given adequate heparin to keep aPTT (activated partial thromboplastin time) between 1.5 and 2.5, plus 5 mg of warfarin. From the fourth day onwards, their warfarin doses were adjusted using International Normalized Ratios (INR; target range: 2 to 3). This prospective cohort was compared with a historical series of 110 patients had been given 10 mg of warfarin on the first 2 days and 5 mg on the third day with adjustments based on INR thereafter. Outcomes analyzed were as follows: recurrence of thromboembolism, bleeding events and time taken to enter the therapeutic range.RESULTS: Efficacy, safety and length of hospital stay were similar in both samples. The sample that were given 10 mg entered the therapeutic range earlier (means: 4.5 days vs. 5.8 days), were on lower doses at discharge and had better therapeutic indicators at the first return appointment.CONCLUSIONS: The 10 mg dosage regimen took less time to attain the therapeutic range and was associated with lower warfarin doses at discharge and better INR at first out-patients follow-up visit.

Keywords

anticoagulants, warfarin, dose-response drug relationship, thrombosis, treatment outcomes

Resumo

CONTEXTO: A melhor dose para o início do tratamento anticoagulante com varfarina vem sendo debatida nos últimos dez anos. Em nosso meio, não observamos nenhum estudo comparativo quanto a estas características.OBJETIVO: Comparar segurança e eficácia de dois esquemas de dosagem inicial de varfarina para tratamento anticoagulante.MÉTODOS: Foram estudados prospectivamente 110 pacientes de ambos os sexos, consecutivos, com indicação de anticoagulação por tromboembolismo venoso ou arterial. Durante os três primeiros dias de tratamento, estes pacientes receberam doses adequadas de heparina (RT - razão dos tempos - alvo entre 1,5 e 2,5) e 5 mg de varfarina, cuja dose foi reajustada a partir do quarto dia pelo Razão Normatizada Internacional - RNI (alvo entre 2 e 3). Esse grupo foi comparado com série histórica de 110 pacientes que receberam 10 mg nos dois primeiros dias, 5 mg a partir do terceiro dia, com ajuste posterior de dose baseado no RNI. Os desfechos foram: recorrência do tromboembolismo, sangramentos e tempo para alcançar níveis terapêuticos.RESULTADOS: A eficácia, a segurança e o tempo de internação foram similares entre os grupos. O grupo que recebeu 10 mg atingiu níveis terapêuticos mais precocemente (média de 4,5 dias × 5,8 dias), sendo as doses na alta menores e os níveis terapêuticos mais adequados na primeira visita de retorno.CONCLUSÃO: O esquema de dosagem de 10 mg proporcionou menor tempo para alcançar nível terapêutico, com menores doses de varfarina na alta e RNI mais adequado no retorno.

Palavras-chave

anticoagulantes, varfarina, relação dose-resposta à droga, trombose, resultado de tratamento

References

Kearon C, Akl EA, Comerota AJ. Antithrombotic therapy for VTE disease: Antithrombotic Therapy and Prevention of Thrombosis. Chest. 2012;141:e419S-94S.

Maffei FHA, Rollo HA, Lastoria S. Trombose venosa profunda dos membros inferiores: tratamento anticoagulante. Doenças Vasclares Periféricas. 2008;Volume 2:1597-610.

Diretrizes. Normas de orientação clínica para a prevenção, o diagnóstico eo tratamento da trombose venosa profunda. J Vasc Bras. 2005;4:S205-20.

Crowther MA, Ginsberg JB, Kearon C. A randomized trial comparing 5-mg and 10-mg warfarin loading doses. Arch Intern Med. 1999;159:46-8.

Eckhoff CD, Didomenico RJ, Shapiro NL. Initiating warfarin therapy: 5 mg versus 10 mg. Ann Pharmacother. 2004;38:2115-21.

Heneghan C, Tyndel S, Bankhead C. Optimal loading dose for the initiation of warfarin: a systematic review. BMC Cardiovasc Disord. 2010;10:18.

Amián A, Rodriguez JN, Muniz R. Comparative study of the stability of oral anticoagulant treatments (warfarin vs acenocoumarol). Sangre (Barc). 1996;41:9-11.

Harper P, Monahan K, Baker B. Warfarin induction at 5 mg daily is safe with a low risk of anticoagulant overdose: results of an audit of patients with deep vein thrombosis commencing warfarin. Intern Med J. 2005;35:717-20.

Harrison L, Johnston M, Massicotte MP, Crowther M, Moffat K, Hirsh J. Comparison of 5-mg and 10-mg loading doses in initiation of warfarin therapy. Ann Intern Med. 1997;126:133-6.

Gurwitz JH, Avorn J, Ross-Degnan D, Choodnovskiy I, Ansell J. Aging and the anticoagulant response to warfarin therapy. Ann Intern Med. 1992;116:901-4.

Maffei FHA, Rollo HA. Trombose Venosa Profunda dos Membros Inferiores: Incidência, patogenia, patologia, fisiopatologia e diagnóstico. Doenças Vasculares Periféricas. 2008;Volume 2:p. 1557-78.

Miyamotto M, Moreira RCR, Toregeani JF, Erzinger FL, Lagos H. Necrose de mama relacionada ao uso de warfarina. J Vasc Bras. 2004;3:52-4.

Monkman K, Lazo-Langner A, Kovacs MJ. A 10 mg warfarin initiation nomogram is safe and effective in outpatients starting oral anticoagulant therapy for venous thromboembolism. Thromb Res. 2009;124:275-80.

Kovacs MJ, Rodger M, Anderson DR. Comparison of 10-mg and 5-mg warfarin initiation nomograms together with low-molecular-weight heparin for outpatient treatment of acute venous thromboembolism. A randomized, double-blind, controlled trial. Ann Intern Med.. 2003;138:714-9.

Wells PS, Le Gal G, Tierney S, Carrier M. Practical application of the 10-mg warfarin initiation nomogram. Blood Coagul Fibrinolysis. 2009;20:403-8.

Quiroz R, Gerhard-Herman M, Kosowsky JM. Comparison of a single end point to determine optimal initial warfarin dosing (5 mg versus 10 mg) for venous thromboembolism. Am J Cardiol. 2006;98:535-7.

Kemkes-Matthes B, Matzdorff A, Heidt M, Winkler L, Bernardo A. Initiation of oral anticoagulant treatment: comparison between different dosage regimens of warfarin and phenprocoumon. Hamostaseologie. 2002;22:47-51.

Holbrook A, Schulman S, Witt DM. Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis. Chest. 2012;141:e152S-84S.

Roberts GW, Helboe T, Nielsen CB. Assessment of an age-adjusted warfarin initiation protocol. Ann Pharmacother. 2003;37:799-803.

Ageno W, Gallus AS, Wittkowsky A, Crowther M, Hylek EM, Palareti G. Oral anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis. 2012;141:e44S-88S.

Santos FC, Maffei FHA, Carvalho LR. Complicações da terapia anticoagulante com warfarina em pacientes com doença vascular periférica: estudo de coorte prospectivo. J Vasc Bras.. 2006;5:194-202.

Sociedade Brasileira de Angiologia e Cirurgia Vascular (SBACV)"> Sociedade Brasileira de Angiologia e Cirurgia Vascular (SBACV)">
5ddd88ee0e882565561da3e9 jvb Articles
1677-7301 (Electronic)
J Vasc Bras ©2024 All rights reserved.

J Vasc Bras

Share this page
Page Sections