Sulfonamides chemical review

The APVMA reviewed the use of sulfonamide antibiotics in food-producing animals because of concerns about the potential for unacceptable residues in food.

In 1989, the Pesticide and Agricultural Chemicals Standing Committee began a reconsideration of sulfonamide antibiotic use in food-producing animals. Concerns about sulfonamide maximum residue limit (MRL) violations in Australian and export markets led to the recommendation by the National Health and Medical Research Council that all sulfonamides used in food-producing animals be assigned MRLs.

In 1989, registrants of sulfonamide antibiotic products were asked to provide all relevant toxicological, residue and metabolism data to support either the establishment or the maintenance of acceptable daily intake values, MRLs and use patterns for their products.

The Pesticide and Agricultural Chemicals Standing Committee’s reconsideration of toxicological data found that only five of the sulfonamide antibiotics could continue to be used in food-producing animals: sulfadimidine, sulfadiazine, sulfadoxine, sulfaquinoxaline and sulfatroxazole. Approvals for all other sulfonamides should be cancelled for use in food-producing animals due to insufficient toxicological data.

In March 1995, on the advice of the standing committee and in the interests of public safety, the APVMA (formerly the NRA) cancelled the use of all other sulfonamides in food-producing animals. The APVMA then began a review of the remaining sulfonamides (sulfadimidine, sulfadiazine, sulfaquinoxaline, sulfadoxine, sulfatroxazole) to determine appropriate MRLs.

In April 2000, the APVMA released the Sulfonamides special review draft report. The report established new MRLs and confirmed existing MRLs for the sulfonamide antibiotics sulfadimidine, sulfadiazine, sulfadoxine, sulfaquinoxaline and sulfatroxazole. The evaluation of residues data found that some uses could be supported, while other uses had insufficient data to support their continued approval.

In August 2000, the APVMA released the Sulfonamides review final report. The report found that sulfadimidine, sulfadiazine, sulfaquinoxaline, sulfadoxine and sulfatroxazole are safe for use in food-producing animals. However, the use of sulfadimidine/sulfadiazine combination products in food-producing animals required additional residue data to support their use and continued registration.

In the final review report, the APVMA recommended:

• cancelling the registration of one anticoccidial product containing sulfadimidine because of insufficient data
• establishing new MRLs for the use of sulfonamides in food-producing animals.