Lack of effect of influenza vaccine on anticoagulation by acenocoumarol.
OBJECTIVE
To analyze the effects of influenza vaccine on patients receiving chronic anticoagulant therapy with acenocoumarol.


METHODS
A prospective trial.


METHODS
Hospital de la Santa Creu i Sant Pau, Barcelona.


METHODS
Forty-three patients who received acenocoumarol, had stable levels of International Normalized Ratio (INR), and did not need dosage modification for four months before entering the study.


METHODS
A study of anticoagulation levels measured by INR at 7, 15, and 30 days from administration of the trivalent vaccine from the 91-92 campaign was conducted.


METHODS
Comparison was made between basal values (day 0) and anticoagulation levels at 7, 15, and 30 days from vaccine administration by means of a repeated-measures ANOVA.


RESULTS
Nine patients (21 percent) had INR levels out of the therapeutic range during the study period. INR increased in three of these patients and decreased in six. There were no significant intraindividual changes in INR values during the time period analyzed (p = 0.125). No hemorrhagic or thrombotic manifestations occurred and no significant changes in renal or hepatic biochemistry were observed.


CONCLUSIONS
Influenza vaccine does not modify acenocoumarol activity in patients receiving long-term anticoagulant therapy.
Souto
J C
JC
Hematology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
Oliver
A
A
Montserrat
I
I
Mateo
J
J
Sureda
A
A
Fontcuberta
J
J
D000074:Acenocoumarol / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D001777:Blood Coagulation / Q000187:drug effects*; D004347:Drug Interactions; D005260:Female; D006801:Humans; D007252:Influenza Vaccines / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014611:Vaccination
D000925:Anticoagulants; D007252:Influenza Vaccines; D000074:Acenocoumarol