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Safety of Intramuscular Influenza Immunization Among Patients Receiving Long-term Warfarin Anticoagulation Therapy

Safety of Intramuscular Influenza Immunization Among Patients Receiving Long-term Warfarin... Abstract Background: The effect of influenza vaccine on the prothrombin time (PT) among patients taking warfarin is unclear, as previous studies have shown conflicting results and the clinical significance of such a purported effect is uncertain. Moreover, to our knowledge, there are no data confirming the safety of intramuscular injections in patients receiving anticoagulant therapy with regard to possible local hematoma formation. We measured the effect of influenza vaccine on the PT among patients receiving long-term warfarin sodium therapy and evaluated the safety of intramuscular injections among them. Methods: Forty-one adult patients who were receiving anticoagulant therapy were given 0.5 mL of influenza vaccine intramuscularly. Prothrombin time and arm girth were measured at baseline and on days 3, 7, and 14 after immunization. Local pain and tenderness were assessed on a five-point scale. Patients and study nurses were blinded to all prior measurements. Differences between baseline PT and that at each subsequent visit and the maximal change in arm circumference from baseline were calculated for each patient. Mean, range, and 95% confidence intervals were calculated for the entire group. Results: There was no statistically significant change in PT between baseline and days 3, 7, and 14 after vaccination, and no significant change in arm circumference was noted. There were no clinically detectable local complications after intramuscular injection and no major or minor bleeding episodes after influenza vaccination. Conclusions: Influenza vaccine has no significant effect on the PT in patients who are being treated with warfarin. Influenza vaccine can be administered intramuscularly to patients who are receiving anticoagulant therapy without the risk of local bleeding complications.(Arch Intern Med. 1995;155:1529-1531) References 1. Centers for Disease Control. Recommendations of the Public Health Service Immunization Practices Advisory Committee—prevention and control of influenza. MMWR Morb Mortal Wkly Rep . 1991;40( (suppl RR-6) ). 2. Kramer P, McClain CJ. Depression of aminopyrine metabolism by influenza vaccination. N Engl J Med . 1981;305:1262-1264.Crossref 3. Arnold WS, Mehta MK, Roberts JS. Influenza vaccine and anticoagulation control in patients receiving warfarin. Br J Clin Pract . 1990;44:136-139. 4. Gomolin IH, Chapron MS, Luhan PA. Lack of effect of influenza vaccine on theophylline levels and warfarin anticoagulation in the elderly. J Am Geriatr Soc . 1985;33:269-272. 5. Lipsky BA, Pecoraro RE, Roben NJ, de Blaquiere P, Delaney CJ. Influenza vaccination and warfarin anticoagulation. Ann Intern Med . 1984;100:835-837.Crossref 6. Farrow PR, Nicholson KG. Lack of effect of influenza and pneumococcal vaccines on anticoagulation by warfarin. J Infect . 1984;9:157-160.Crossref 7. Bussey HI, Saklad JJ. Effect of influenza vaccine on chronic warfarin therapy. Drug Intell Clin Pharm . 1988;22:198-201. 8. Weibert RT, Lorentz SM, Norcross WA, Klauber MR, Jagger PI. Effect of influenza vaccine in patients receiving long-term warfarin therapy. Clin Pharm . 1986;5:499-503. 9. Kramer P, Tsuru M, Cook CE, McClain CJ, Holtzman JL. Effect of influenza vaccine on warfarin anticoagulation. Clin Pharmacol Ther . 1984;35:416-418.Crossref 10. Gardner MJ, Altman DJ, eds. Statistics With Confidence . London, England: British Medical Journal 1989:20-27. 11. McEvoy GK, ed. Anticoagulants. In: American Hospital Formulary Service Drug Information . Bethesda, Md: American Society of Hospital Pharmacists Inc; 1994: 874-888. 12. Patriarca PA, Kendal AP, Stricof RL, Weber JA, Meissner MK, Dateno B. Influenza vaccination and warfarin or theophylline toxicity in nursing home residents. N Engl J Med . 1983;308:1601-1602.Crossref http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Internal Medicine American Medical Association

Safety of Intramuscular Influenza Immunization Among Patients Receiving Long-term Warfarin Anticoagulation Therapy

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Publisher
American Medical Association
Copyright
Copyright © 1995 American Medical Association. All Rights Reserved.
ISSN
0003-9926
eISSN
1538-3679
DOI
10.1001/archinte.1995.00430140104011
Publisher site
See Article on Publisher Site

Abstract

Abstract Background: The effect of influenza vaccine on the prothrombin time (PT) among patients taking warfarin is unclear, as previous studies have shown conflicting results and the clinical significance of such a purported effect is uncertain. Moreover, to our knowledge, there are no data confirming the safety of intramuscular injections in patients receiving anticoagulant therapy with regard to possible local hematoma formation. We measured the effect of influenza vaccine on the PT among patients receiving long-term warfarin sodium therapy and evaluated the safety of intramuscular injections among them. Methods: Forty-one adult patients who were receiving anticoagulant therapy were given 0.5 mL of influenza vaccine intramuscularly. Prothrombin time and arm girth were measured at baseline and on days 3, 7, and 14 after immunization. Local pain and tenderness were assessed on a five-point scale. Patients and study nurses were blinded to all prior measurements. Differences between baseline PT and that at each subsequent visit and the maximal change in arm circumference from baseline were calculated for each patient. Mean, range, and 95% confidence intervals were calculated for the entire group. Results: There was no statistically significant change in PT between baseline and days 3, 7, and 14 after vaccination, and no significant change in arm circumference was noted. There were no clinically detectable local complications after intramuscular injection and no major or minor bleeding episodes after influenza vaccination. Conclusions: Influenza vaccine has no significant effect on the PT in patients who are being treated with warfarin. Influenza vaccine can be administered intramuscularly to patients who are receiving anticoagulant therapy without the risk of local bleeding complications.(Arch Intern Med. 1995;155:1529-1531) References 1. Centers for Disease Control. Recommendations of the Public Health Service Immunization Practices Advisory Committee—prevention and control of influenza. MMWR Morb Mortal Wkly Rep . 1991;40( (suppl RR-6) ). 2. Kramer P, McClain CJ. Depression of aminopyrine metabolism by influenza vaccination. N Engl J Med . 1981;305:1262-1264.Crossref 3. Arnold WS, Mehta MK, Roberts JS. Influenza vaccine and anticoagulation control in patients receiving warfarin. Br J Clin Pract . 1990;44:136-139. 4. Gomolin IH, Chapron MS, Luhan PA. Lack of effect of influenza vaccine on theophylline levels and warfarin anticoagulation in the elderly. J Am Geriatr Soc . 1985;33:269-272. 5. Lipsky BA, Pecoraro RE, Roben NJ, de Blaquiere P, Delaney CJ. Influenza vaccination and warfarin anticoagulation. Ann Intern Med . 1984;100:835-837.Crossref 6. Farrow PR, Nicholson KG. Lack of effect of influenza and pneumococcal vaccines on anticoagulation by warfarin. J Infect . 1984;9:157-160.Crossref 7. Bussey HI, Saklad JJ. Effect of influenza vaccine on chronic warfarin therapy. Drug Intell Clin Pharm . 1988;22:198-201. 8. Weibert RT, Lorentz SM, Norcross WA, Klauber MR, Jagger PI. Effect of influenza vaccine in patients receiving long-term warfarin therapy. Clin Pharm . 1986;5:499-503. 9. Kramer P, Tsuru M, Cook CE, McClain CJ, Holtzman JL. Effect of influenza vaccine on warfarin anticoagulation. Clin Pharmacol Ther . 1984;35:416-418.Crossref 10. Gardner MJ, Altman DJ, eds. Statistics With Confidence . London, England: British Medical Journal 1989:20-27. 11. McEvoy GK, ed. Anticoagulants. In: American Hospital Formulary Service Drug Information . Bethesda, Md: American Society of Hospital Pharmacists Inc; 1994: 874-888. 12. Patriarca PA, Kendal AP, Stricof RL, Weber JA, Meissner MK, Dateno B. Influenza vaccination and warfarin or theophylline toxicity in nursing home residents. N Engl J Med . 1983;308:1601-1602.Crossref

Journal

Archives of Internal MedicineAmerican Medical Association

Published: Jul 24, 1995

References