Streptomycin, dihydrostreptomycin, streptomycin/penicillin and dihydrostreptomycin/penicillin chemical review

The APVMA reviewed the use of streptomycin, dihydrostreptomycin and the combination products of streptomycin/penicillin and dihydrostreptomycin/penicillin in food-producing animals because of concerns about efficacy, possible risks to the public from residues in food, and the potential for residues in meat from treated animals to harm Australian meat and offal exports.

In 1997, the APVMA (formerly the NRA) began the review of (dihydro) streptomycin and (dihydro) streptomycin/penicillin combination products after the Meat Research Corporation and the Victorian Department of Natural Resources and Environment advised of concerns. These concerns were about the efficacy of combination products and the possible risk to the Australian trade in meat from streptomycin residues in meat and offal from treated food-producing animals.

In 1999, the APVMA released the (Dihydro) streptomycin/penicillin combination products and (dihydro) streptomycin products review final report. We were not satisfied that the use of (dihydro) streptomycin/penicillin in combination was as effective as penicillin alone, or that the continued use (dihydro) streptomycin products—alone or in combination—would not be an undue risk to Australian trade in meat and offal.

The key findings of the final review report were as follows:

• Combination injectable (dihydro) streptomycin/penicillin products should no longer be used in food-producing animals. Using the combination of (dihydro) streptomycin and penicillin, when penicillin alone was an effective treatment, had the potential to lead to overuse of the (dihydro) streptomycin and promote antibiotic resistance.
• The use of (dihydro) streptomycin/penicillin combination products, even at recommended label rates, had the potential to lead to residue violations.
• Injectable products containing (dihydro) streptomycin should no longer be used in food-producing animals, as there was insufficient data to establish suitable withholding periods. The continued use of these products in food-producing animals could not be supported on the grounds of residues and trade.

In the report recommended:

• cancelling the use of (dihydro) streptomycin and penicillin in combination, for use in food-producing animals
• cancelling the use of (dihydro) streptomycin in food-producing animals (the APVMA will only allow limited off-label use of these products under veterinary permit; for more information, see the advisory note below)
• strengthening warnings on product labels by amending product labels to specify that (dihydro) streptomycin and (dihydro) streptomycin/penicillin combination products should not be used in food-producing animals, with effect from 30 June 1999
• withdrawing the maximum residue limits (MRLs) for poultry (the review found that the residue data did not support the existing MRLs for poultry).

On 1 October 1999, the APVMA cancelled the registration of four (dihydro) streptomycin/penicillin combination products at the request of the registrants.

Advisory note: the APVMA believes that using (dihydro) streptomycin products for certain purposes under veterinary permit is necessary on the grounds of human health, animal welfare and trade. These uses include the removal of the carrier state of leptospirosis in cattle, pigs and sheep, the treatment of campylobacteriosis in bulls and the treatment of live cattle for export to countries that require it. For these conditions, the APVMA has issued permits for the off-label use of (dihydro) streptomycin.