NEW YORK (Reuters Health) - Several cases of anaphylaxis or other allergic reactions have been seen in patients following cystoscopy with instruments disinfected with Cidex ortho-phthalaldehyde (OPA), according to a report in the August Journal of Allergy and Clinical Immunology.

"I think that OPA is a highly allergenic substance and should have very limited use or be taken off the market altogether," Dr. William N. Sokol from University of California Irvine College of Medicine, told Reuters Health. "With so many of our patients being subjected to endoscopic procedures and the increasing use of OPA, the possibility of sensitization and subsequent reaction is great."

Dr. Sokol reports nine episodes of anaphylaxis following cystoscopy in four patients after cystoscopy with instruments that had been cleaned with Cidex OPA.

All nine reactions were severe, Dr. Sokol explains, including urticaria in nine episodes, angioedema in seven, penile itching/edema in seven, laryngeal edema in seven, loss of consciousness in three, and convulsions in one.

In all cases, Dr. Sokol notes, the anaphylactic reactions were initially attributed to other agents known to be associated with allergic reactions (including antibiotics and local anesthetics).

In skin testing after the anaphylactic episodes, all four patients developed large immediate and delayed reactions to OPA, Dr. Sokol reports.

Three patients subsequently underwent repeat cystoscopy after the urology practice switched back to a glutaraldehyde disinfectant. Their postprocedure courses were uneventful.

"This product has only recently been released and widely used," Dr. Sokol said. "I anticipate a near epidemic of reactions to be seen in the coming months. Although time will tell, the reactions are so severe that I think the product should seriously be considered for removal from the market."

He added: "Just today I had a telephone call from a pulmonologist who told me about a patient who experienced lingual and laryngeal edema following (upper endoscopy) in which OPA was used to clean the scope. The patient had two episodes; the first was mild, and the second resulted in endotracheal intubation and four days in the ICU."

Dr. Sokol concluded, "The importance of this reaction in a non-urological patient is that the patients at risk, as I suggested in my article, are not only urology patients, but any patient who is subject to endoscopy or to any other instrumentation in which OPA is used."

J Allergy Clin Immunol 2004;114:392-397

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