[Intramuscular route for the administration of the anti-flu vaccine in patients receiving oral anticoagulation therapy]. / Utilización de la vía intramuscular para la administración de la vacuna antigripal en pacientes que reciben anticoagulantes orales.

BACKGROUND AND OBJECTIVE: Comparison of safety and effectiveness of the intramuscular (IM) (deltoid) vs subcutaneous (s.c.) administration of the flu vaccine (FV) in patients on oral anticoagulation therapy. PATIENTS AND METHOD: It was a phase IV, simple blind, 2-parallel groups, randomized trial developed in an urban primary care setting. We included patients taking oral anticoagulation therapy without FV contraindications. The IM administration of the FV in the experimental group was compared with a SC administration in the control group. RESULTS: 59 patients were included. The two groups were comparable at the beginning of the study. INR was not modified following s.c. (p = 0.38) or i.m. (p = 0.49) administration. No systemic side effects were observed. More cutaneous lesions were observed in the S.C. group (71.4%) when compared with the i.m. group (25.8%; p < 0.0001). For the remaining variables, we observed a tendency towards more reported pain in the SC group (35.7 vs 22.6%) and a larger brachial diameter (42 vs 29%) without significant differences. 3.2% of patients in the i.m. group and 7.1% in the s.c. group developed influenza symptoms without significant differences. CONCLUSIONS: Even though the results must be interpreted with caution, currently there appears to be no apparent contraindication for the i.m. administration of the FV. When it is administered subcutaneously, it tends to cause more side effects.

Utilización de la vía intramuscular para la administración de la vacuna antigripal en pacientes que reciben anticoagulantes orales / Intramuscular route for the administration of the anti-flu vaccine in patients receiving oral anticoagulation therapy

FUNDAMENTO Y OBJETIVO: Comparar la seguridad y la efectividad de la administración intramuscular deltoidea de la vacuna antigripal (VAG) respecto a la subcutánea en pacientes que reciben anticoagulantes orales. PACIENTES Y MÉTODO: Ensayo clínico aleatorizado de fase IV, simple ciego, llevado a cabo por un equipo de atención primaria (EAP) urbano en pacientes con anticoagulación oral sin contraindicación para la VAG. Las variables analizadas fueron la edad, el sexo, la diámetro braquial, las lesiones elementales, el dolor (según una escala analógica visual), los efectos secundarios sistémicos, la razón normalizada internacional (INR) y la aparición de episodio gripal hasta junio de 2002. RESULTADOS: Se incluyó a 59 pacientes (28 en los que la VAG se administró por vía subcutánea y 31 por vía intramuscular). No se modificó el INR después de la administración subcutánea (p= 0,38) ni intramuscular (p = 0,49). No se observaron efectos secundarios sistémicos. Se observaron más lesiones cutáneas en la administración subcutánea (71,4%) que en la intramuscular (25,8%) (p < 0,0001), número necesario a tratar (NNT) 2 (intervalo de confianza [IC] del 95%, 1-4). En el resto de variables se observa una tendencia a que el grupo de administración subcutánea presente más dolor (el 35,7 frente al 22,6%) y un mayor diámetro braquial (el 42,9 frente al 29,0%), sin diferencias significativas. Presentaron clínica compatible con gripe un 3,2% del grupo intramuscular y un 7,1% del grupo de administración subcutánea, sin ser diferencias significativas. CONCLUSIONES: Aunque los resultados deben interpretarse de forma prudente, no hay ninguna justificación actual para contraindicar la administración de la vacuna antigripal por vía intramuscular; incluso la administración por vía subcutánea presenta más efectos secundarios

BACKGROUND AND OBJECTIVE: Comparison of safety and effectiveness of the intramuscular (IM)(deltoid) vs subcutaneous (s.c.) administration of the flu vaccine (FV) in patients on oral anticoagulation therapy. PATIENTS AND METHOD: It was a phase IV, simple blind, 2-parallel groups, randomized trial developed in an urban primary care setting. We included patients taking oral anticoagulation therapy without FV contraindications. The IM administration of the FV in the experimental group was compared with a SC administration in the control group. RESULTS: 59 patients were included. The two groups were comparable at the beginning of the study. INR was not modified following s.c. (p = 0.38) or i.m. (p = 0.49) administration. No systemic side effects were observed. More cutaneous lesions were observed in the S.C. group(71.4%) when compared with the i.m. group (25.8%; p < 0.0001). For the remaining variables, we observed a tendency towards more reported pain in the SC group (35.7 vs 22.6%) anda larger brachial diameter (42 vs 29%) without significant differences. 3.2% of patients in theim. group and 7.1% in the s.c. group developed influenza symptoms without significant differences. CONCLUSIONS: Even though the results must be interpreted with caution, currently there appears to be no apparent contraindication for the i.m. administration of the FV. When it is administered subcutaneously, it tends to cause more side effects