Anaphylaxis: hydroxyzine reduced reactions to contrast media

Clinical bottom line (level 1b)

  1. Patients without history of allergy who underwent contrast media studies and who received hydroxyzine 12 hours before, were less likely to have adverse reactions compared with placebo (NNT = 9 at minutes) .
Bertrand et al: Radiology 1992; 184: 383-384
Expires November 2004

The study

Double-blinded ?concealed randomised trial with intention-to-treat
Setting: acute hospital, France

400 patients (aged mean 59, 63% male) undergoing intravenous urography, CT, or venography of the lower limb

Excluded if
  • aged < 18
  • clinical history of allergy (swelling of the face, urticaria, rhinitis, conjunctivitis, skin rash or hypersensitivity to shellfish
  • atopy (asthma, hay fever, or eczema)
  • previous reactions to contrast media or drug sensitivities


Note:
  • All patients received a dose of iodinated low-osmolality contrast medium


Control Group: (n = 200, 200 analysed): placebo
Experimental Group: (n = 200, 200 analysed): hydroxyzine 100 mg by mouth 12 hours before examination

100% followed for ? hours 100
Outcome notes:
  • adverse reaction : nausea, vomiting, skin rash, other

The evidence

Outcome Time to outcome CEREERRRR
(95% CI)		ARR
(95% CI)		NNT
(95% CI)
adverse reaction weeks 25
(12.5%)		 2
(1.00%)		 92%
(67% to 98%)		 11.5%
(6.71% to 16.3%)		 9
(6 to 15)

Comments

  1. Hydroxyzine is an H-1 antihistamine.
  2. No adverse reactions nor major anaphylactic reactions were reported.
  3. The results can easily be applied to hospital patients. For outpatients there is a problem: because hydroxyzine is sedating it is difficult for drivers.
  4. This study suffers from a lack of clarity regarding its outcomes measure.  The characterization of “adverse reactions” does not distinguish between anaphylactoid (urticaria/angioedema, bronchospasm, hypotension, etc) vs. non-anaphylactoid (nausea/emesis, flush, etc.) events.  The magnitude of anaphylactoid reactions from intravenous contrast infusions, which is similar to penicillin and hymenoptera venom sting reactions, is 1-2%, of which 0.1-0.2% are severe in nature (Bochner BS, Lichtenstein LM.  Anaphylaxis.  N Engl J Med  1991; 324: 1785-90); for this reason, a study of 400 subjects is too small to make general recommendations.

Citation

  1. Bertrand PR, Soyer PM, Rouleau PJ, et al: Comparative randomized double-blind study of hydroxyzine versus placebo as premedication before injection of iodinated contrast media. Radiology 1992; 184: 383-384
Search Terms: contrast media and complications in Medline
Contributor: Mike Bennett & Chris Ball, November 1999
Reviewer: Richard Koopmans, David Lang

Clinical Question.
Patient receiving an injection of ionic contrast media
Intervention or Exposure hydroxyzine
Comparison placebo
Outcome anaphylaxis