In July 1993, the National Health and Medical Research Council reconsidered halquinol because of toxicological concerns and the potential risk to human health from dietary residues.
In December 1993, the National Drugs and Poisons Scheduling Committee (NDPSC) of the National Health and Medical Research Council placed halquinol in Appendix M of the Standard for the Uniform Scheduling of Drugs and Poisons, as the toxicological data were outdated and insufficient to establish a no-effect level for halquinol and hence establish an acceptable daily intake.
In August 1994, the NDPSC assessed new halquinol data provided by the registrant, Ciba-Geigy Ltd. The NDPSC concluded that there were insufficient toxicological data to support the continued use of halquinol in veterinary products. The committee recommended that halquinol remain in Appendix M and that the APVMA review the registration of halquinol and the approvals of all products containing it.
In November 1994, the registrant advised that they had voluntarily ceased marketing all products containing halquinol and would phase out all existing stocks. In November 1994, the APVMA conducted a special review of halquinol based on the NDPSC’s recommendation, and formally consolidated all previous regulatory actions.
