Jump to comment:

• Use of intravenous cyclizine in cardiac chest pain
  Roger A Cooke
  Published on: 9 January 2006

• Published on: 9 January 2006

  Use of intravenous cyclizine in cardiac chest pain

  • Roger A Cooke, Immediatte Care Physician
  • Other Contributors:
    • Matthew W Cooke (Professor Emergency Medicine,Warwick Medical School)

  Dear Editor,

  The quoted aim of best evidence topic reviews (BETs) is to produce a clinical bottom line which indicates, in the light of the evidence found, what the reporting clinician would do if faced with the same scenario again[1]. Such an objective is only achieved if the recommendation of the BET accurately reflects the results of the evidence review. May and Kumar[2] conclude that “cyclizine should be avoid...

  Show More

  Dear Editor,

  The quoted aim of best evidence topic reviews (BETs) is to produce a clinical bottom line which indicates, in the light of the evidence found, what the reporting clinician would do if faced with the same scenario again[1]. Such an objective is only achieved if the recommendation of the BET accurately reflects the results of the evidence review. May and Kumar[2] conclude that “cyclizine should be avoided in patients with acute coronary events”, although we note with interest and concern that this conclusion differs from the on-line version on the BEST Bets website, which is that “There appears to be no firm evidence that cyclizine increases morbidity and mortality in patients with myocardial ischaemia”.

  We have further concerns about the conclusion in the paper edition of the journal. The paper reviews a single 16 year old study, which looked at a small number of patients suffering from heart failure. To their credit May and Kumar observe that it was a small study in a very specific group of patients. Unfortunately the published clinical bottom line appears to draw conclusions that are not limited to treatment of patients suffering from heart failure.

  The study by Tan, Bryant and Murray[3], which was reviewed, contained measurement data when cyclizine was given 30 minutes before diamorphine. While cyclizine significantly increased heart rate, right atrial, pulmonary arterial, pulmonary artery wedge and systemic arterial pressures, the subsequent diamorphine tended to change those variables toward the basal values, although right atrial and pulmonary arterial pressures remained significantly above basal values. Tan et al quoted work that concluded that cyclizine may be useful if avoidance or prompt reversal of the hypotensive effect of opiate is required[4],which potential benefit does not appear to have been considered by May and Kumar.

  It is also relevant to observe that no data is given for simultaneous administration of cyclizine with opiate, for cyclizine administered after the opiate and the study excluded use of any other drugs.. Since cyclizine may be administered simultaneously with, or shortly after the opiate in the clinical situation, considerable caution is required if the conclusions of this study are to be translated into advice about clinical care.

  The clinical bottom line has the disadvantage of being a negative recommendation, which begs the question "if not cyclizine what should I use?" The authors have noted that the effects of other antiemetics have not been studied, and do not therefore exclude the possibility that other anti-emetics may have more frequent or more severe adverse effects than cyclizine. We repeated their search strategy but replacing the cyclizine search with metoclopramide or stemetil/prochlorperazine, revealing no studies of the effects of these two commonly used drugs. A Cochrane study is being undertaken to review other anti-emetics[5], and recommendations regarding use of cyclizine or other anti-emetics in acute coronary events must surely await a broader review of this type.

  In summary, the clinical bottom line propounded by May and Kumar does not accurately reflect the findings of the single study review; we would suggest that it would have been more appropriate to conclude that "There is the possibility of adverse homodynamic effects of cyclizine in patients with heart failure, and of beneficial effects in patients with opiate induced hypotension; the effects of other known anti-emetics are unknown."

  References

  1. Carley SD ed Towards evidence based emergency medicine: best BETs from Manchester Royal Infirmary Emerg Med J 2006; 61-66.

  2. May G, Kumar R Use of intravenous cyclizine in cardiac chest pain Emerg Med J 2006; 61-62.

  3. Tan LB, Bryant S, Murray RG detrimental Haemodynamic effects of cyclizine in heart failure Lancet 1988; 1: 560-1.

  4. Christie G, Gershon S, Gray R, Shaw FH, McCance I, Bruce DW Treatment of certain effects of morphine Br Med J 1968; I: 675-678.

  5. Smith E, Wasiak J, Boyle M. Prophylactic antiemetic therapy in the emergency and ambulance setting for preventing opioid induced nausea and vomiting. (Protocol) The Cochrane Database of Systematic Reviews 2004, Issue 3.

  Show Less

  Conflict of Interest:
  None declared.

  • Back to top