CHYMOPAPAIN REVISED BOXED LABEL WARNING ADVISES MDs

CHYMOPAPAIN REVISED BOXED LABEL WARNING ADVISES MDs to "abandon" the injection procedure if "there is any question regarding needle tip location within the nucleous of the disc or if the contrast agent extravasates into the subarachnoid space." The warning notes that "chymopapain is toxic when injected into the subarachnoid space. Some radio-opaque contrast media are neurotoxic. Great care must be taken to assure that the dura is not penetrated and that chymopapain or contrast agents do not enter the subarachroid space." The revised warning on Smith Labs Chymodiactin and Omnis Surgical's Discase follows reports of serious neurological reactions including paraplegia and cerebral hemorrhage, following administration of chymopapain. Smith Labs and Omnis Surgical explained the label changes in letters to MDs and hospital pharmacists. In addition to the boxed warning at the top of the package insert, the information is expanded on in the warnings and adverse reactions sections of the labeling. FDA has been discussing the label change, instituted at Smith Labs request, with the mfrs. for some time. The agency and Smith Labs commented on the adverse reaction situation at a recent Radiopharmaceutical Drugs Advisory Cmte. meeting ("The Pink Sheet" May 21, T&G-6). The revised boxed warning also discusses the reported association of the drug with acute transverse myleitis and acute transverse myleopathy. The association has been reported at a rate of about one in 18,000, the labeling states. "Although cause and effect relationship to the injection of chymopapain itself has not been established, the reported rate is significantly higher than the incidence reported in the medical literature." Patents at increased risk appear to be those "receiving injections at two or more disc spaces following discography," the warning explains.