Safety of the Intramuscular Route of the Anti-Flu Vaccine in Patients Receiving Oral Anticoagulation Therapy

Study Overview
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Brief Summary
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Until now, the best administration route of the anti-flu vaccine for patients receiving long term oral anticoagulation therapy has been the subcutaneous one; the intramuscular route has not been recommended because it may increase the risk of muscular haematoma. Although this practice is widely extended, no significant differences between the safety of both routes have been found. Some authors, analysing a small group of patients, affirm that the anti-flu vaccine can be administered safely by the intramuscular route on patients receiving long term oral anticoagulation therapy, while a previous opinion article recommended the subcutaneous route without any scientific evidence. Due to this, the investigators have done a clinical trial with the aim of determining the safety and effectiveness of the flu-vaccine intramuscular route in patients receiving long term oral anticoagulation therapy and also to analyse the possible interactions between the vaccine and the oral anticoagulant treatment.

Detailed Description
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Phase IV, simple blind, 2-parallel groups, multicentric randomized trial where each patient will receive a single dose of the recommended by the WHO anti-flu vaccine for the 2003-2004 period, the control group will receive it subcutaneous and intervention group intramuscular. The assignation to each group will be randomized. The study included 4 basic areas of Barcelona city. Three visits have been scheduled for each patient: moment 0, 24 hours and 10 days after the vaccination, and a 7 month follow up period to control the incidence of the flu.

Official Title
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Phase IV, Simple Blind, 2-Parallel Groups Randomized Trial to Evaluate the Safety and Effectiveness of the Intramuscular Vs Subcutaneous Route for the Administration of the Anti-Flu Vaccine in Patients Receiving Oral Anticoagulation

Conditions
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Influenza

Intervention / Treatment
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* Procedure: Influenza vaccine intramuscular administration route


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with oral anticoagulation therapy Patients who agree to be vaccinated Patients who agree to participate in the study Patients older than 18 Exclusion Criteria: Allergy or hypersensibility to egg, chicken proteins, any component of the vaccine (neomycin, octoxinol-9 or formaldehyd) INR greater than 4 in the past 2 months Previous major bleeding Patients with dementia or with legal tutoring

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 95 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Intervention/Treatment |
| --- |
|Procedure: Influenza vaccine intramuscular administration route|nan|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| local pain (scores greater than 3 in the analogic visual scale of pain) |  |  | 
| microbiologically diagnosed flu (yes/no) |  |  | 
| International Normalized Ratio (INR) to check the interaction between the vaccine and the oral anticoagulation therapy |  |  | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| increase of the arm perimeter greater than 1 cm |  |  | 
| local elemental skin lesions |  |  | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Influenza Vaccines, Acenocoumarol, Drug Administration Routes, Anticoagulants