Ethidimuron Chemical Review

In August 1991, the National Health and Medical Research Council (NHMRC) began a reconsideration of ethidimuron because of concerns about a lack of toxicological data.

The NHRMC requested more information from the registrant, Bayer, but the information was not provided. In August 1994, ethidimuron was placed in Appendix M of the Standard for the Uniform Scheduling of Medicines and Poisons, which was for ‘substances for which registration under agricultural and veterinary chemicals legislation cannot be supported by scheduling until further toxicological information becomes available’.

In August 1994, Bayer advised that it wished to voluntarily discontinue the registrations of products containing ethidimuron when existing stocks had been exhausted. A two-year phase-out period was requested to use up existing retail stocks.

In August 1994, the APVMA (then the NRA) was advised of concerns over the gaps in the ethidimuron toxicological database and began a special review of ethidimuron to formally consolidate the previous regulatory action by the NHMRC.

The APVMA completed the special review of ethidimuron in September 1994 but did not publish a final report. The APVMA found that there was insufficient toxicological data to support the continued registration and use of ethidimuron and the associated maximum residue limits (MRLs).

In the report, the APVMA recommended:

• cancelling the active constituent approval, with effect from 30 June 1997cancelling the MRLs for ethidimuron, with effect from 30 June 1997cancelling all registrations and relevant approvals of products containing ethidimuron, with effect from 30 June 1997.

No products containing ethidimuron are currently registered for use in Australia.