Clanobutin sodium chemical review

In 1993, the Drugs and Poisons Schedule Standing Committee noted that there were insufficient residues data to fully assess the possible risks posed to humans from the ingestion of residues of clanobutin sodium.

In 1994, the Advisory Committee on Public Health considered clanobutin sodium and noted that no acceptable daily intake (ADI) or maximum residue limits (MRLs) had been set for this compound. The advisory committee recommended that it not be used for food-producing animals.

In 1997, the APVMA (then the NRA) began a review of clanobutin sodium following advice from the Therapeutic Goods Administration about its concerns over the potential risk to the public from long-term exposure to residues in food.

As part of the review, the APVMA asked the single registrant, Boehringer Ingelheim Pty Ltd, to provide more information and data to support the continued use and registration of the only clanobutin sodium product on the market, Bykahepar Digestive Stimulant. These data were required to address toxicological concerns and to establish an ADI and MRLs for food-producing animals.

In 1998, the review was suspended because the registrant of Bykahepar Digestive Stimulant indicated that they would not provide the data necessary to complete the residues assessment and that they would not be renewing the registration of their product.

In 1998, the registration of Bykahepar Digestive Stimulant was transferred to another registrant, Schering-Plough, which renewed the registration of the product. At that time, the APVMA reactivated the review because the original concerns about residues had not been adequately addressed.

In May 1999, the APVMA completed the review of clanobutin sodium but no final report was released. The key findings were:

• the potential for long-term exposure at any level in humans was very low, as there was only one registered product for single animal use by injection
• there were insufficient data to support the existing withholding periods for clanobutin sodium.

There were insufficient data for the Therapeutic Goods Administration to set an ADI for clanobutin sodium, but it was considered that no MRLs needed to be set; with appropriate withholding periods, no residues should be detected in tissues or milk from animals treated with clanobutin.

In the final report, the APVMA recommended increasing the withholding period for meat from three to 28 days and increasing the withholding period for milk from nil to three days.

The APVMA was satisfied that by varying these conditions of registration the use of the product could continue.